Titre : |
The liquid metal look |
Type de document : |
texte imprimé |
Auteurs : |
Wei Liu, Auteur ; Carolyn Lavallee, Auteur |
Année de publication : |
2007 |
Article en page(s) : |
p. 18-22 |
Langues : |
Anglais (eng) |
Catégories : |
Absorbeurs de rayonnement ultraviolet Oxychlorure de bismuth Photostabilité Pigments métalliques Réflectance
|
Index. décimale : |
667.2 Colorants et pigments |
Résumé : |
Recent advances mean bismuth oxychloride pigment is being used for variety of purposes. This paper looks at its application in coatings.
The liquid metal look is essentially a smooth, highly reflective, non-grainy appearance. This is accomplished by using either a continuous film or by using very thin platelets, on the order of 30-50 nanometers, to reduce the scattering of light from edges of platelets. It has been desirable in the automotive industry for some time and is now making an appearance in other coating applications, such as teletronics.
This is accomplished by using either a continuous film or by using very thin platelets of a highly reflective pigment. One of the pigments that satisfy these requirements is bismuth oxychloride. This pigment has been better know for applications such as button and costume jewellery coatings, but recent advances make it feasible for less traditional applications as well, such as achieving the liquid metal effect.
Bismuth oxychloride is made by the reaction of bismuth nitrate in acid solution with chloride. By suitably controlling pH and temperature, the formation of BiOCl is thermodynamically preferred over Bi2O3, bismuth oxide. With very fine control of these same parameters the crystals grow as very thin patelets. The chemical reaction is as follows :
Bi(NO3)3 + H2O + 3NaCl --> BiOCl + 2HCl + 3NaNO3
The resulting platelets are about 90nm thick at the edge and somewhat thicker in the middle. It is the shape of these platelets, along with the index refraction (about 2.0), that is responsible for its pearlescent appearance. |
Note de contenu : |
- Bi(NO3)3 + H20 + 3NaCl -> BiOCl + 2HCl + 3NaNO3
- Optical properties vs effect
- UV stability
- Applications
- Applications in coatings
- Blended
- Test result
- UV absorber
- TABLE : 1. Physical properties of BiOCl and TiO2 coated mica - 2. L change for BiOCl crystal stabilised by cerium hydroxide in medium shade after 240hr QUV 340 exposure - 3. L* change for BiOCl crystal stabilised by cerium hydroxide and UV absorber in medium shade after 240hr QUV exposure |
En ligne : |
https://drive.google.com/file/d/1bguGWEO5jMB1nJugjzoXYUUtA2H_EmKg/view?usp=drive [...] |
Format de la ressource électronique : |
Pdf |
Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27409 |
in POLYMERS PAINT COLOUR JOURNAL - PPCJ > Vol. 197, N° 4510 (03/2007) . - p. 18-22