Pigment Blue 28(Cobalt Blue) is also named king blue, thenard blue or cobalt ultramarine, is a very bright blue. Cobalt blue is a mixed metal oxide pigment of spinel pattern. It has excellent heat resistance, light-fastness, acid resistance, alkali resistance and non-toxic, so it can be used in the area which required high heat resistance, excellent color stability and ageing resistance.
It can be use for fluorocarbon coatings, heat resistant coatings, plastics, ceramics, grass and artists' colors.
Density (g/cm3) | 4.3 |
PH value | 7.5 |
Oil Absorption(g/100g) | 25 |
105℃Volatile Matter% | ≤0.5 |
Water soluble Matter% | ≤0.5 |
Residue on 45um Mesh% | ≤0.1 |
Heat resistant | 1000℃ |
Light Resistant | 8 |
Acid resistant | 5 |
Alkali Resistant | 5 |
Because it is a spinel mixed oxide, Pigment black 28 retains its color and structure during high-temperature processing (ceramic firing and many bake cycles). For extreme sintering or specialized glass melts, choose grades formulated for those temperatures and confirm performance by lab trial.
Yes — it shows strong chemical resistance to many acids, alkalis and solvents. However, chemical resistance can vary with particle surface treatment and binder system, so validate in your exact formulation.
Pigment black 28 contains cobalt in its mixed-oxide structure. While it is an inorganic, stable pigment, regulatory and safety requirements depend on the end use and region. Always consult the product's SDS and regulatory documentation before use in consumer applications.
