Infrared Spectra of U.S. Automobile Original Finishes (1998–2000).IX. Identification of Bismuth Oxychloride and Silver/White Mica Pearlescent Pigments Using Extended RangeFT‐IRSpectroscopy,XRFSpectrometry, andSEM/EDSAnalysis

Abstract

Bismuth oxychloride (BiOCl) was the first viable synthetic pearl pigment developed 50 years ago. It was only used for a limited time period in automotive paint (model years 1998-2000), serving to produce luster for a single Chrysler black metallic color. Identification of this pigment in an unknown automotive paint can thus facilitate determination of the vehicle of origin. Bismuth oxychloride imparts effects similar to those produced by silver/white mica pearlescent pigments, and such a pigment was used together with bismuth oxychloride in at least one original equipment manufacturer (OEM) basecoat. Silver/white micas are now used primarily in white pearl tricoat systems. This article describes the identification of bismuth oxychloride and silver/white mica pearlescent pigments in automotive finishes using FT-IR spectroscopy, X-ray fluorescence (XRF) spectrometry, and SEM/EDS analysis. Data for some cadmium pigments, which were used in automotive paint several decades ago, are also presented as they produce infrared absorptions similar to that of bismuth oxychloride.

Bismoclite (BiOCl) in the San Francisco de los Andes Bi–Cu–Au Deposit, Argentina. First Occurrence of a Bismuth Oxychloride in a Magmatic–Hydrothermal Breccia Pipe and Its Usefulness as an Indicator Phase in Mineral Exploration

“…It was the first feasible synthetic pearlescent pigment developed over 50 years ago [33]. The two main modern commercial forms of pearlescent pigments are bismuth oxychloride and titanium dioxide (or ferric oxide) coating on micas [32,34]. The highest quality synthetic BiOCl-based pearlescent pigment occur as 11 to 15 µm sized hexagonal-shaped platelets due to their narrow particle size, high refractive index and flat shape.…”

“…The highest quality synthetic BiOCl-based pearlescent pigment occur as 11 to 15 µm sized hexagonal-shaped platelets due to their narrow particle size, high refractive index and flat shape. Bismuth oxychloride has a smoother surface and approximately twice the reflectance of the best titanium dioxide mica-based alternatives, and similar reflectivity to aluminum [32,34,35].…”

“…Bismoclite is used for coating metal, plastic, paper, leather and even wood to sharply bring out features in furniture [32,34,35]. Bismuth oxyhalide has been used in cosmetics since ancient Egypt, and has been used widely in recent years in various beauty care products, mainly makeups as it has a silky feel, good slip, good adhesion and an iridescent effect that helps to conceal skin imperfections due to its light reflecting property [34,35].…”

“…Bismuth oxyhalide has been used in cosmetics since ancient Egypt, and has been used widely in recent years in various beauty care products, mainly makeups as it has a silky feel, good slip, good adhesion and an iridescent effect that helps to conceal skin imperfections due to its light reflecting property [34,35]. Bismoclite can also give a metallic appearance to certain non-metallic materials and it is the most common coating used to make simulated pearls [32,35].…”

“…Due to the lack of covalent bonds, most of the absorption features are located in the far infrared region [34]. Bismoclite has two sharp absorptions at approximately 528 and 180 cm´1, as well as two broad absorptions across the ranges 470 to 250 cm´1 and 170 to 85 cm´1 (Table 8) [68].…”