Research Background of Black Zirconia Ceramic Composite
Zirconia has a wide range of uses due to its superior mechanical, thermal, and electrical qualities in structural materials, optical components, oxygen sensor components, and fuel cells. Black zirconia ceramics have recently emerged as a new choice material for high-end decoration as a result of its good mechanical qualities, vivid color, metallic sheen, and non-allergic impact, which coincides with the significant growth in people's desire for decorations. However, traditional black zirconia ceramics cannot fulfill the needs of high-blackness mobile phone boards and other appearance components due to issues such as brittleness, weakness, poor color uniformity, insufficiency of blackness, good light transmittance, and insufficiency of color hiding power.
Problems Solved by Black Zirconia Ceramic Composite
Exterior ceramic pieces have struggled with color and robustness for a long time. The current technological method for changing the color of zirconia ceramics is to blacken them in a vacuum, reducing atmosphere, or inert atmosphere to create oxygen vacancies, which create point defects in the color center and cause effects on light absorption. Doping zirconia with colorant oxides like iron, cobalt, and nickel is a somewhat comparable technique. This method involves adding colorants to increase the zirconia material's ability to absorb light, which in turn improves the zirconia's ability to hide things and its overall blackness. In terms of strength, the existing technical solution is typically to directly ball mill zirconia and other additives to prepare slurry. However, the quantity of silica and the particle size of silica are not analyzed in detail, which results in an unreasonable strength and brittleness of the molded porcelain body. This article presents a black zirconia ceramic composite with high strength, high blackness, and high lightproof performance, which may be used to address the aforementioned limitations of existing solutions.
Production Method of Black Zirconia Ceramic Composite
Adding a black colorant to the zirconia ceramic powder and adjusting the particle size of the additional silica and alumina can increase the zirconia ceramics' concealing power and blackness, lower their light transmittance, and improve the form of the ceramic body. Exceptional color and durability are guaranteed by the product's high mechanical strength.The following components are included in the composition: iron oxide, cobalt oxide , aluminum oxide , zinc oxide, yttrium oxide , titanium oxide, and bismuth oxide . Zirconia with hafnium oxide and silica make up the remaining components. The aforementioned proportions of each component can guarantee consistency in the created ceramic's strength, hardness, L value, and ceramic density.
The addition of silica to the composition improves the toughness and bending strength of the shaped porcelain body by increasing the glass phase in the zirconia, which protects the crack tip of the zirconia from damage due to the glass's flexibility. Simultaneously, it should be emphasized that silica content should be kept below 1.0% since too much glass phase would significantly enhance the brittleness of the formed porcelain body. In addition, aggregation during sintering might reduce the gloss of the molded body and disrupt the color homogeneity if the silica concentration is too high. The ceramic powder can be made tougher by the presence of both silica and alumina. Large and tiny zirconia particles can be combined to increase compactness between particles, decrease porosity, and lower the shrinkage rate of the formed ceramic body during the sintering process. This results in a ceramic with greater flexural strength. After sintering, the porcelain body produced using this method might achieve a shrinkage rate of 15-30%.
Conclusion
Based on assuring the ceramic's blackness and covering power, the black zirconia ceramic composite described in this article increases the ceramic's strength, especially the three-point bending strength, which can reach more than 1600Mpa. In addition, the powder excludes the use of chromium-containing chemicals, especially hexavalent chromium, so that the resulting ceramic items have environmentally friendly characteristics.