Colorants Inorganic Pigments

DEU: Diese Untersuchung befasst sich mit der Synthese von Zinkferrit (ZnFe2O4) und der Analyse seiner thermochromen Eigenschaften. Ziel ist es, die Eignung von ZnFe2O4 als anorganisches Farbpigment für temperaturanzeigende Beschichtungen in der industriellen Betriebssicherheit zu prüfen. Zudem wird die Temperaturbeständigkeit des Materials analysiert. Unabhängig davon liefern die Ergebnisse eine solide Grundlagenforschung des
Materials. Die Synthese des Zinkeisenoxids und seiner Edukte wird detailliert betrachtet,
da sie potenzielle Auswirkungen auf die Thermochromie haben könnte.

Diese Arbeit stellt ein noch laufendes Projekt dar. Änderungen sind also vorbehalten. Alle Angaben ohne Gewähr.
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ENG: Title: Study of Thermochromism of ZnFe₂O₄; Zn²⁺[Fe²⁺Fe³⁺]O₄ (Zinc iron oxide; Zinc ferrite). Abstract: This study deals with the synthesis of zinc ferrite (ZnFe2O4) and the analysis of its thermochromic properties. The aim is to demonstrate the suitability of ZnFe2O4 as inorganic color pigment for temperature-indicating coatings in industrial operational safety. In addition, the temperature resistance of the material is increased analyzed. Regardless, the results provide solid basic research materials. The synthesis of zinc iron oxide and its educts is examined in detail, as it could have potential effects on thermochromism. (This paper is in German).

This paper is a work in progress (WIP). So updates on newer versions might appear. I dont claim legal responsibility for any information displayed. All rights reserved.

A colorant which is able to reflect the 49% of near infrared component of solar radiation is considered as a cool colorant. A twofold approach to study the role of size and dopant on the near infrared reflective properties of metal oxide nanoparticles is reported in this work. It was found that the template assisted synthesis of α-Fe 2 O 3 , c-CoO, and sol-gel synthesis of Cr 2 O 3 provided nanoparticles with very low size and uniform size distribution, which eventually translated into a high NIR reflectance. Cummative effect of size and doping was also found in the case of Cr 2 O 3 nanoparticles doped with rare earth metal ions. This study conclusively provides an insight to how near infrared properties can be conferred to metal oxides with colors such as brown, black, blue and green through appropriate doping and size control.

High near-infrared (N-IR) reflecting nanopigments (Ce 2− x M x SiO 5 ; where M = Mo 6+ and x ranges from 0 to 0.4) based on cerium silicon doped with Mo 6+ were synthesized by epoxide assisted sol-gel process. The pigment and nanopigment samples were characterized by means of XRD, UV-Vis-NIR spectrophotometer and CIE L * a * b * color measurement. The analysis showed that the pigments crystallized completely even at 850°C with particle size less than 45-60 nm. The substitution of Mo 6+ for Ce 3+ in Ce 2 SiO 5 induced the absorption in the visible region (420-500 nm) which imparts change in the pigments color from white to light yellow. The developing nanopigments have high N-IR reflectance, hence it use as 'cool pigments'.

This study reports the effect of the crystallinity degree and structural order of the supramolecular architectures of the perylene derivative Paliogen® Black L0086 (P-black) on the near-infrared (NIR) transparent, reflective and cooling characteristics of 75 μm thick acrylic coatings. Notably, XRD and solid-state NMR investigations revealed that on passing from the commercially available P-black C to the synthetic form P-black S, the average crystallinity passed from 20 to 48% flanked by a superior structural order that enhanced the mean crystallite width from 21.7 to 39.1 nm and maximum length from 1.5 μm to 6.5 μm, as evidenced by SEM micrographs. UV-VIS-NIR spectroscopic analyses of the coated surfaces confirmed the NIR transparent and reflective characteristics of the P-black pigment that was particularly relevant in the case of the pigment synthetic form. NIR reflectance enhancements from 25% to 50% were actually recorded on black surfaces on passing from the commercial to the synthetic form of the pigment dispersed into the acrylic coatings. This feature was reflected on the solar reflectance and the cooling effect, with values boosted from 9.9% to 18.2% and from 2.3 � C to 3.8 � C, respectively.

EXPERIMENTAL ALCHEMY. Much is said and written regarding alchemy all across the world, in what could be called a renaissance of alchemical studies. However, relatively little is done in terms of actual alchemical laboratory work. The aim of the project described herein was to show how crucial the development of technical alchemical practice was along the centuries, in the discovery of an immense number of substances, processes and operations, which were of paramount importance in the establishment of modern chemistry. Alchemy is often derided in many circles. On the contrary, for two thousand years it constituted the basis of humankind's understanding of the material world and the changes undergone by compounds and materials. Here we present an experimental reconstitution of several alchemical discoveries of great importance, using old descriptions followed by modern characterizations. The results were often startling and demonstrated how ancient wisdom bore fruit in different ways, even in the absence of our present-day means of analysis.

The novel two-step synthesis method decreasing the calcining temperature necessary for formation of spinel lattice and as well for reaching of bright and clear hue of the pigments prepared were investigated. This work aims to utilization of DTA for synthesis monitoring. Influence of raw materials and temperature of calcination on color properties were observed. The characterization of the samples was performed by X-ray diffraction and colorimetry in the CIE L * a * b * system. It was proved that the black spinel pigment Cu 2.3 Mn 2.8 Cr 4.9 O x can be prepared at finally temperature 700°C as one-phase system with high quality black hue.

Copper (II) aluminate, CuAl 2 O 4 , which is known to be an inverse spinel contains a d 9 metal ion and possesses interesting electronic, magnetic and catalytic properties and is used in industry as ceramic pigments, coatings and catalysts. Al 2 O 3 with 10 mol% Cu (AlCu10) was synthesized by the polymeric precursor method varying the pH of the precursor solution with addition of ammonium hydroxide and ethylenediamine. It was shown that the pyrolysis of the polymeric chain occurs in higher temperatures for samples prepared in higher values of pH. The colorimetric coordinates exhibit dependence with pH and with the increase of annealing temperature. AlCu10 samples prepared with higher values of pH present lower values of colorimetric coordinates, indicating alterations in its color. The luminosity parameters L* increase also as a function of pH.

Os minerais estão presentes no cotidiano de todas as pessoas de diferentes maneiras e pensando que estes são compostos naturais, compreender mais sobre eles possibilita um olhar mais crítico para a natureza. Nesse sentido, esse trabalho tem como objetivo analisar uma prática pedagógica que teve como intuito construir conceitos acerca do tema Elementos e Compostos dos Minerais. A prática emergiu da disciplina Metodologia do Ensino de Ciências, ofertada pelo curso de licenciatura em Ciências Biológicas da Universidade Federal de Lavras. Ao final da prática, foi pedido aos participantes que apontassem os pontos positivos e os pontos a serem melhorados da mesma. Essas falas foram analisadas no âmbito da pesquisa qualitativa, mais especificamente pela análise por categorias, que é derivada da Análise de Conteúdo. Após a análise foi possível constituir três categorias: "Recursos pedagógicos", "Desenho como forma de incentivar a criatividade" e "Domínio do conteúdo por parte da professora". Foi possível perceber a relevância dos recursos pedagógicos, pois foram capazes de instigar a curiosidade dos estudantes. Ainda, a utilização da prática de desenhar foi fundamental para instigar a criatividade dos estudantes, visto que os instigou a participar da aula. Ademais, foi possível perceber a importância do domínio do conteúdo pela professora, visto que é o arcabouço teórico-prático, o qual envolve, dentre outros, saberes científicos e pedagógicos, que possibilita a formação de cidadãos críticos e reflexivos.

Solar spectral behavior of nanopigments has been an important issue in many practical relevance due to their tunable properties. There are extensive literatures on radiative transfer through pigmented coating but they are generally restricted to a small range of materials with specific properties and particular applications. Current study, on the other hand, concerns with a comprehensive look at contribution of fundamental characteristics of nanopigments on spectral behavior of the pigmented coatings. In order to accomplish this goal, a Discrete Ordinate Method (DOM), known as Multi Flux (MF) model in color science, has been applied on spherical particles embedded in nonabsorbing medium, and their optical responses including reflectance, transmittance and absorption has been studied over solar spectrum, with special emphasis on VIS region. The effect of various indices of refraction, particle sizes and volume fractions has been further investigated. Obtained results reveal that, pigments with different fundamental and morphological structures represent interesting optical behavior which is very promising in optimization of spectrally selective pigmented coatings. The results from MF model were subsequently validated using spectrophotometric measurements on Titanium dioxide nanopigments coated on white polyester substrate, which represented a good agreement with collected data from MF model.

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

An inorganic yellow pigment based on TiO 2 containing minor amounts of bismuth and molybdenum compounds was developed without rare earths or highly toxic elements. The material was produced starting from a composition of 99% (mol%) of rutile TiO 2 and 1% of MoO 3 , which were previously mixed and calcined at 1200°C. The composition consisted of 99.8% of the above mixture and 0.2% of bismuth(III) nitrate basic hexahydrate. This powder mixture was homogenized and calcined in a tubular furnace at 1200°C, applying different heating rates: 1, 30, 40, and 60°C/min. The yellow color was attributed to the presence of a-Bi 2 O 3 , c*-Bi 2 MoO 6 , and Bi 2 Ti 2 O 7 phases. The powder particle size proved suitable for using the material as an inorganic pigment for polymers. The technological application of the pigment was tested in high-density polyethylene.

O referido artigo é um relato de experiência de uma aplicação didática e dia-lógica para alunos dos segundos anos e terceiros anos do ensino médio da escola pública em meio à pandemia do Covid-19, que tem como objetivo aproximar através da interdisciplinaridade a Arte urbana do grafite e o ensino de Física estabelecendo uma conexão entre o ensino e a aprendizagem. A análise do discurso, segundo o teórico Mikhail Bakhtin, nasce além das rela-ções da metalinguística, ou seja, se insere a partir das interações discursivas entre os indivíduos. Na perspectiva das relações humanas, a ciência e a Arte fazem parte da formação social e da evolução tecnológica. A construção da interdisciplinaridade entre o ensino de Física e a Arte urbana do grafite trazem as abordagens entre as relações que construíram a nossa sociedade. A escola é um espaço provocador de possibilidades reflexivas e que promove o diálogo, trazendo a interação da análise do discurso em sala de aula. Dessa maneira os gêneros d...

This study reports for the first time the use of thermoplastic hollow microspheres (THM) in combination with a perylene bisimide pigment (Paliogen® Black L0086 (P-black)) for the preparation of acrylic coatings with nearinfrared (NIR) reflecting and cooling characteristics. VIS-NIR spectra showed that P-black solid dispersions provide reflectance values in agreement with the P-black content and its crystalline nature. The introduction of THM with average diameter of 25 ± 5 μm with the same weight content of P-black did not substantially affect the crystalline nature of the pigment within the organic coating even if a decreasing of the long range order in the molecular packing of the perylene chromophores emerged from XRD and solid-state NMR investigations. Noteworthy, the addition of the THM successfully contributed in the exponential raising of the solar reflectance (SR) of coated black substrates, i.e. reaching up to the 22% at the highest organic layer thickness of 255 μm. The effective combination between THM and P-black was well reflected on the temperature of the back side of the coated surface after irradiation with a solar simulator, i.e. with a maximum cooling effect of about 6°C.

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

In this research ceramic pigments have been synthesized with crystalline spinel structure and chromium based with a stoichiometry ACr 2 O 4. A was an element with +2 valence metal, in this case, metals were zinc and iron, these pigments have been synthesized by non-conventional methods like the co-precipitation assisted by ultrasound and high milling energy. Pigments were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometry, and colorimetric CIELab method. Results showed that it was possible to obtain a crystallin desired structure at temperatures below 900˚C by non-conventional methods. These results showed the advantages of ceramic pigments obtained by alternative routes, because it was possible to have a better control over stoichiometry and colorimetric structure properties. Furthermore, they were obtained at temperatures lower than those used by the traditional ceramic route.

O presente texto relata a experiencia de uma pratica de ensino por investigacao de funcoes inorgânicas que foi desenvolvida com alunos da primeira serie do ensino medio de uma escola publica estadual. Trata-se de uma proposta de ensino baseada na aprendizagem ativa, como uma ferramenta para sair do ensino tradicional de recepcao de conteudo. A pratica foi dividida em duas partes: uma de investigacao, onde os alunos tinham que observar as formulas de algumas substâncias inorgânicas e organizar tais substâncias em conjuntos; na segunda parte os alunos testavam essas substâncias para certificarem-se da organizacao que haviam proposto. Com esse trabalho pode-se perceber a importância de inserir o aluno na construcao do conhecimento, uma vez que atuando na estruturacao da aprendizagem ele compreende melhor o conteudo a ser estudado .

Recently, the polymer pyrolysis method by means of acrylic acid and metal salts has been developed for preparation of different metal oxides. The co-polymeric precursor compounds are schematically supposed to have metal ions attached by the ionic bonds to carboxylate ions in a polymeric chain or between the polymeric chains. This uniform distribution of metal ions and Ti(OH)4 in the precursor favors the formation of uniformly distributed solid solution of the metallic oxides in the pyrolysis process. In this work, a trimetallic oxide as a pigment with high near-infrared (NIR) reflectance was synthesized by reaction of titanium butoxide with metal acetate (M = Mn, Ni, Ti) in acrylic acid via polymer pyrolysis method. The pigment properties of the oxide were investigated by X-ray diffraction (XRD) and field scanning electron microscopy (SEM), NIR diffuse reflectance spectroscopy (DRS).

In the present research, CoAl 2 O 4 nano-pigment powder was synthesized by a combination of citrate-gel processing and microwave-assisted heating route. Blue CoAl 2 O 4 ceramic nano-pigment was rapidly obtained after calcination in microwave oven. Thermal decomposition behavior of the as-synthesized precursor was monitored by DTA/TGA (differential thermal analysis/thermo-gravimetric analysis). The effects of various microwave exposure times (8-15 min) on the phase composition and difference in color were evaluated through X-ray diffraction (XRD) and CIE Lab color space system, respectively. The mean crystallite size of blue nano-pigment powders was determined by the X-ray line broadening technique. The optimum time of pigment processing by utilizing microwave oven was obtained at 15 min to get a sufficiently intense blue color. Scanning electron microscopy (SEM) and field emission SEM (FE-SEM) characterizations were employed to observe the size and morphology of optimum powder particles. Particles size analysis by SEM indicated that the majority of quasi-spherical particles have a small size in the range of nano which was in agreement with XRD results, while FE-SEM studies confirmed flower-like morphology of asprepared powder.

Disclosed is a method of preparing pigmentary chromium oxide nano particles having 50 percent particle size less than about 100 nm. Preparation of nano chromium (III) oxide is investigated by thermal decomposition method. According to the disclosed method, a substantially dry solid composition of potassium dichromate and carbon active is heated in CO 2 atmosphere to a temperature of about 600ºC for 1hour. Thereafter, the solid Cr 2 O 3 product was washed twice with distilled water.

Radar-absorbent materials, used in stealth technology for defense aircrafts, vehicles, satellites, etc. from radar detection, are commonly based on graphite or semiconductive particles embedded in a polymer matrix. In this study, we employed Co2+ ion-substitution to improve Vis-NIR reflectivity of hydroxyapatite (Ca10(PO4)6(OH)2, HAP) powder. HAP:Co with nominally 5 at.% of Co was prepared with hydrothermal processing of a precipitate. Synthesized powder was characterized by XRD, Raman and ATR-FTIR spectroscopy, FE-SEM and TEM. Thermal stability of HAP:Co powder was examined by simultaneous TG-DTA analyzer. To modify its optical properties and obtain powders with a varietty of color tone, the HAP:Co powder was calcined at 800, 1000, and 1100 °C, in an air atmosphere, for 1 hour. Afterward, the calcined particles were used to prepare composites with poly(vinyl butyral), (PVB); the concentration range was 1 wt.% of the HAP:Co in PVB. The composite coatings, in the form of thin films o...

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

We describe the synthesis and structure of Barium sulfate nanoparticles by precipitation method in the presence of water soluble inorganic stabilizing agent, sodium hexametaphosphate, (NaPO 3) 6. The structural parameters were refined by the Rietveld refinement method using powder X-ray diffraction data. Barium sulfate nanoparticles were crystallized in the orthorhombic structure with space group Pbnm (No. 62) having the lattice parameters a = 7.215(1) (Å), b = 8.949(1) (Å) and c = 5.501(1) (Å) respectively. Transmission electron microscopy study reveals that the nanoparticles are size range, 30-50 nm. Fourier transform infrared spectra showed distinct absorption due to the SO 2− 4 moiety at 1115 and 1084 cm −1 indicating formation of barium sulfate nanoparticles free from the phosphate group from the stabilizer used in the synthesis.

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

A CONTEXTUAL EXPERIMENT IN HIGHER EDUCATION. Metallic oxides are used in cosmetic shadows formulations in order to highlight the area around the eyes, with different colors. Due to the close proximity to the eye mucosa, these products are a potential source of metal intoxication in human body. Based in this fact, several analytical methods to quantify metals in cosmetic shadows have been proposed in the literature. This paper, propose a contextual experiment to investigated the presence of Al 3+ , Fe 3+ and Cu 2+ using UV-VIS spectrophotometric and complexation reactions in solvent mixtures to generate cromophore species. These experiments have the potential to insert a contextual discussion in chemistry and pharmaceutical graduation courses, making a meaningful experimentation in the formative attribute of these courses.

For building applications, coatings are needed in order to obtain an attractive appearance and protection against the outdoor environments. Buildings are responsible for consumption of cooling energy. Cool coatings applied over buildings surface provide an effective solution for passive cooling of building indoors and influencing local outdoor microclimate, mitigating urban heat islands effect (UHIE). Cool coatings have to resistant to weathering and ageing. For this reason, we developed near infrared (NIR) reflective pigments with the aim to add in binder and obtaining a cool coating. A series of pigments displaying YIn0.9Mn0.1O3–ZnO stoichiometry was synthesized by sol-gel route. The dried gel precursor was calcined at different temperatures for 2h (650°C, 800°C and 850°C) to observe the formation of a light brown pigment and two different blue shades. Precursors and calcined final pigments were characterized by using physicochemical analyses. The colour of pigments was studied us...

In this paper, we report on the facile synthesis method to obtention of nickel titanate (NiTiO 3) nanoparticles through pyrolysis of polymeric precursor method. The pyrolysis behaviors of the polymer precursors prepared via the in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry. The structural and morphological characteristics of the products were studied by powder X-ray diffraction and transmission electron microscope. The results reveal that ilmenite NiTiO 3 nanoparticles with spherical-like shape are obtained through pyolysis Ni-Ti polyacrylate precursor at above 600 ºC. The mean particle size of NiTiO 3-600 ºC and NiTiO 3-800 ºC is about 30 nm and 60 nm, respectively. Ultraviolet-visible (UV-Vis) near infrared (NIR) reflectance spectra study show that the NiTiO 3 nanoparticles have a high reflection peak in ~580 nm, which justifies the deep and brilliant yellow color of this pigment. The average reflectance of NiTiO 3-600 ºC and NiTiO 3-800 ºC in NIR range is 62.1% and 58.8%, respectively. We have observed brilliant yellow color and high UV-Vis-NIR reflectance of NiTiO 3 nanoparticles. Moreover, these NiTiO 3 nanoparticles have great potential in serving as cool pigment for building coating.

Este trabalho apresenta o resultado parcial do desenvolvimento de um experimento multidisciplinar de baixo custo, atraves da projecao de uma gota de agua iluminada por uma lanterna laser que funciona como um microscopio. O microscopio de gota ou microscopio de Planinsic, foi montado pelo aluno bolsista no âmbito de um Projeto de Ensino denominado Insercao de Fisica Moderna e Nanotecnologia no campus de Capivari. O experimento escolhido permite explorar varios topicos do curriculo de Ciencias da Natureza, Matematica e Informatica, no entanto, nessa parte inicial foi priorizado sua aplicacao em optica geometrica que e um dos topicos da disciplina de Fisica e estudo do movimento browniano para o qual foi realizado um videoanalise e utilizado o recurso computacional disponivel no software livre Tracker . O trabalho ja foi apresentado na forma de sugestao de material instrucional para alunos do curso de Licenciatura em Quimica do campus de Capivari e no evento denominado Sciense Day orga...

O presente estudo tem como objetivo compreender de que modo o uso de mapas conceituais como ferramenta metodológica no Projeto Trajetórias Criativas pode potencializar o ensino e a aprendizagem. O estudo foi realizado em uma escola pública estadual do município de Alvorada, Rio Grande do Sul, Brasil. Os sujeitos de pesquisa foram seis professores e três estudantes do Projeto Trajetórias Criativas. A coleta de dados se deu por meio de entrevistas semiestruturadas, gravadas em áudio e posteriormente transcritas. As respostas foram analisadas a partir da análise textual discursiva, proposta por Moraes e Galiazzi (2013). Os resultados apontam para o destaque dessa metodologia como ferramenta capaz de auxiliar o professor em sua ação pedagógica pelo fato de constituir-se em um modo de avaliação diferenciado e apresentar versatilidade em sua aplicação. Em relação ao aprendizado dos estudantes, foi possível compreender que a ferramenta é capaz de valorizar os interesses e conhecimentos que...

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

Este artigo apresenta uma sequencia didatica (SD) com o uso de Objetos de Aprendizagem (OA) sobre Termodinâmica. A SD foi planejada de acordo com a metodologia dos Tres Momentos Pedagogicos (TMP) de Delizoicov e Angotti (1991) e disponibilizada aos estudantes no MOODLE por meio do software de autoria eXe Learning. As interacoes ocorreram com o uso das ferramentas forum e chat. A SD e um subproduto de uma pesquisa que teve como intuito investigar as contribuicoes dos OA para o desenvolvimento do pensamento critico dos estudantes a partir das aulas de Fisica. Esta foi desenvolvida com dois grupos de estudantes da 2a serie do Ensino Medio, de uma escola estadual do interior do Rio Grande do Sul no ano de 2010 e posteriormente seus resultados foram analisados a luz dos indicadores de pensamento critico de Newman, Webb e Cochrane.

Assessment of the state of a pigment dispersion in powder coatings is hindered by the lack of a simple and effective method of evaluation, particularly during the production process. A method for evaluating dispersion quality in cured powder coatings or in samples taken immediately after the extrusion process is described in this paper. Quantitative information of pigment dispersion were obtained using plasma etching-SEM-image analysis. In order to correlate the differences in the extrusion equipment and, consequently, the energy input of the dispersion process, two different formulations were studied, each prepared using three different extrusion units. The procedures are described in detail and the results are compared to those obtained using colour difference measurements. Pigment size distribution plots correlate well with measured colour differences and with the energy inputs of the different extrusion units used.

Inorganic NiTiO 3 nano-pigments have received recent attentions as possible candidates for cool pigment materials to be used in building roofs and facades. In this paper, we have attempted to develop an innovative low temperature (50 C) synthesis pathway for obtaining NiTiO 3 nanocrystals based on an ultrasound-assisted wet chemical processing method. The crystallite size, average particle size and band gap are found to be 11 nm, in the range of 10e20 nm and 3.72 eV, respectively. Ultravioletevisible (UV evis) reflectance spectra show that NiTiO 3 nanoparticles have a high reflection peak at~580 nm, which is associated with the brilliant yellow color of these nano-pigments. Moreover, these NiTiO 3 nanoparticles have great potential in serving as cool pigment for building coating. We believe that the method developed in this work provides a simple, cost-effective, and convenient route for synthesizing a variety of perovskite materials for assembling in nanotechnology.

This work aimed to explore the approximation between the History of Science and the teaching of Chemistry, using Inorganic Pigments in an interdisciplinary and contextualized way. The study involved the intervention of the teacher/researcher of Inorganic Chemistry offered to students of vocational education and the results confirmed the importance of this space for valuing science.
Este trabalho objetivou explorar a aproximação entre História da Ciência e o ensino de Química, utilizando Pigmentos Inorgânicos de forma interdisciplinar e contextualizada. O estudo envolveu intervenção do professor/pesquisador de Química Inorgânica oferecida a alunos do ensino profissionalizante e os resultados confirmaram a importância deste espaço para valorização da ciência.

This article presents results from the application of interdisciplinary didactic-pedagogical intervention for Chemistry Teaching (CT) through a perspective based on the History of Science (HC), highlighting the History of Chemistry (HQ). It was developed with students from the High School Integrated with the Technician in Chemistry, at the Federal Institute of Education, Science, and Technology of São Paulo. This project made it possible to articulate Chemistry, Art and History in a contextualized and coherent way with current proposals in the documents that organize Brazilian education.
Este artigo apresenta resultados da aplicação de uma intervenção didático-pedagógica interdisciplinar para o Ensino de Química (EQ) através de perspectiva baseada na História da Ciência (HC), destacando-se a História da Química (HQ). Foi desenvolvido com alunos do Curso Médio Integrado ao Técnico em Química, no Instituto Federal de Educação, Ciência e Tecnologia de São Paulo. Este trabalho faz parte da pesquisa de mestrado em andamento e caracteriza-se pela abordagem qualitativa.Este projeto possibilitou articular Química, Arte e História de forma contextualizada e coerente com propostas vigentes nos documentos que organizam a educação brasileira.

Covering of blemishes, mechanical damages etc by way of pigments are essential steps in leather processing. Like other industries, leather industry is also facing the challenge of replacing pigments based on lead, chromium (VI), cadmium etc. This paper reports the synthesis of rare earth based colorants for surface coating applications. Pigments have been well characterized by XRD, SEM, particle size measurements and measurement of hiding power and mass tone. While individual rare earth metal ion based doped colorants are ideal for the fashion world, the conventional leather which is predominantly brown and black require cheaper environment friendly alternatives. Mixed rare earth oxide based colorants and transition metal ion doped pigments developed from chromium shavings are presented as possible alternatives to toxic pigments. Applicat ion of mixed rare earth based pigments in leather coloration is discussed in detail.

Poly(methyl methacrylate); Rare earth element; Luminescent materials; Tristimulus values and color parameters; Absorption and extension coefficients. KEYWORDS ABSTRACT In the present work, composites of poly(methyl methacrylate)/alkali rare earth aluminate photoluminescent pigment (PMMA/AREAPP) (100/0, 98/ 2, 96/4, 94/6, and 92/8 wt/wt%) were prepared using mixture technique. The pigment has the composition formula of MeO.xAl 2 O 3 .ySiO 2 :Eu (Me = Ca, Mg, Sr, Ba, x = 0.5-2.0, y = 0.005-0.5) which is activated by rare earth element (Eu). The reflectance spectra and the tristimulus values as well as the color parameters were employed to characterize and reveal the miscibility map and the relationship of the structure properties. The study has been extended to include the absorption and extension coefficients of the prepared composites, the band tail width and band gap energies for the composites. From the obtained results, it is found that the organic parts are attached with the ino...

Apresenta-se neste trabalho os resultados obtidos após a aplicação da Sequencia Didática A Química e a Arte das Pinturas Rupestres , que promoveu a Interdisciplinaridade e Contextualização no estudo dos Óxidos. Nesta proposta, a Química e sua relação com os pigmentos inorgânicos naturais teve papel fundamental no desenvolvimento dos conteúdos supramencionados.
This work presents the results obtained after the application of the Didactic Sequence Chemistry and the Art of Rock Paintings, which promoted Interdisciplinarity and Contextualization in the study of Oxides. In this proposal, Chemistry and its relationship with natural inorganic pigments played a fundamental role in the development of the aforementioned contents.

The combination of white or colorless oxides (MgO, Al 2 O 3 , ZnO) with colorant ions (Co 2+) generates colored pigments (pink, blue, green). The color is caused by the insertion of the colorant ion in the respective crystal lattices (periclase, alumina, wurtzite), as verified by X-ray diffraction. Absorption spectra in the visible region show analogous triplet behavior of the absorption bands for the doped alumina and wurtzite samples but a difference in tetrahedral distortion, which generates blue and green pigments. In contrast, cobalt-doped periclase has color-related parameters related to the pink color. Crystallite and particle sizes show nanometric dimensions in the range of 20-60 nm (magnesium), 20-180 nm (aluminum), and 40-220 nm (zinc). The color is related to the shape (crystalline phase), size, and presence of chromophore ions with absorption in the visible region. Colorimetric studies (CIE L*a*b*) show variations between colors as a function of the polysaccharide that is used (starch or pectin) as fuel. The color variation is subtle in some cases but is significantly noticeable in other cases. Commercial colorless ink dispersion (10% m/m) shows excellent compatibility with the maintenance of hues and a slight increase in color saturation (C*).

Commercially available spinel cobalt blue (CoAl 2 O 4) utilizes a significant amount of carcinogenic Co 2+ , which makes its synthesis more hazardous and environmentally harmful. Considerable effort has been put into developing more environmentally benign and robust blue pigments to replace cobalt blue. A new class of blue pigments with tunable hue were prepared. The solid solution series, CaAl 12−2x Co x Ti x O 19 (0 < x ≤ 1), crystallizes in a hexagonal mineral hibonite (CaM 12 O 19) structure with five distinct crystallographic sites for M cations (M = Al, Co, and Ti). The origin of intense blue color is attributed to a synergistic effect of allowed d−d transitions involving the chromophore Co 2+ in both tetrahedral and trigonal bipyramidal crystal fields. Compared with commercial cobalt blue, these tunable hibonite blues possess a reddish hue that intensifies the blue color as observed in Y(In,Mn)O 3 (YInMn) blues, with a significant reduction of Co 2+ concentration from 33% to as low as 4% by mass. A significant advantage of hibonite blues over cobalt blue is the substantial reduction in carcinogenic cobalt content while enhancing the color properties at a reduced cost for raw materials.

The combination of white or colorless oxides (MgO, Al 2 O 3 , ZnO) with colorant ions (Co 2+) generates colored pigments (pink, blue, green). The color is caused by the insertion of the colorant ion in the respective crystal lattices (periclase, alumina, wurtzite), as verified by X-ray diffraction. Absorption spectra in the visible region show analogous triplet behavior of the absorption bands for the doped alumina and wurtzite samples but a difference in tetrahedral distortion, which generates blue and green pigments. In contrast, cobalt-doped periclase has color-related parameters related to the pink color. Crystallite and particle sizes show nanometric dimensions in the range of 20-60 nm (magnesium), 20-180 nm (aluminum), and 40-220 nm (zinc). The color is related to the shape (crystalline phase), size, and presence of chromophore ions with absorption in the visible region. Colorimetric studies (CIE L*a*b*) show variations between colors as a function of the polysaccharide that is used (starch or pectin) as fuel. The color variation is subtle in some cases but is significantly noticeable in other cases. Commercial colorless ink dispersion (10% m/m) shows excellent compatibility with the maintenance of hues and a slight increase in color saturation (C*).

In this research ceramic pigments have been synthesized with crystalline spinel structure and chromium based with a stoichiometry ACr 2 O 4. A was an element with +2 valence metal, in this case, metals were zinc and iron, these pigments have been synthesized by non-conventional methods like the co-precipitation assisted by ultrasound and high milling energy. Pigments were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), spectrophotometry, and colorimetric CIELab method. Results showed that it was possible to obtain a crystallin desired structure at temperatures below 900˚C by non-conventional methods. These results showed the advantages of ceramic pigments obtained by alternative routes, because it was possible to have a better control over stoichiometry and colorimetric structure properties. Furthermore, they were obtained at temperatures lower than those used by the traditional ceramic route.

Strontium zirconate (SrZrO 3) powders have been synthesized by the polymeric precursor method after heat treatment at different temperatures for 2 h in oxygen atmosphere. The decomposition of precursor powder was followed by thermogravimetric analysis, X-ray diffraction (XRD) and Fourier transform Raman (FT-Raman). The UVevis absorption spectroscopy measurements suggested the presence of intermediary energy levels in the band gap of structurally disordered powders. XRD, Rietveld refinement and FT-Raman revealed that the powders are free of secondary phases and crystallizes in the orthorhombic structure.

We describe a blue/green inorganic material, Ba 3 (P 1−x Mn x O 4) 2 (I) based on tetrahedral MnO 3− 4 :3d 2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the MnO 3− 4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P-O/Mn-O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. Keywords. Blue/green inorganic material; barium phosphate/manganate(V); tetrahedral manganate(V); blue/green chromophore; ligand field tuning of colour.

The aim of the present work is to study the magnetic properties of nanocrystals of ZnO(Co) prepared by two methods of synthesis. We used the microwave assisted hydrothermal synthesis and traditional wet chemistry method followed by calcination. The detailed structural characterization was performed by means of X-ray diffraction and micro-Raman spectroscopy measurements. The magnetic properties were studied by means of AC susceptibility v. All samples demonstrated Curie-Weiss behavior at higher temperatures. For calcination process, the negative values of the Curie-Weiss h temperature were observed indicating the predominance of antiferromagnetic interactions. For samples prepared by hydrothermal synthesis, we observed the breakdown of predominance of antiferromagnetic interactions.