Synthesis And Characterization Of Cobalt Blue Particleless Ceramic Ink

Nowadays,ceramic ink-jet printing technology was developed rapidly,which was widely applied in the field of ceramic decrotion.Currently,the domestic-use ceramic ink was prepared by dispersing submicronic or nanometric pigment particles with dispersant.However,the existence of insoluble particles in the ink will unavoidably bring nozzle clogging,which increased the damaged probability of the printer head.In addition,precipitation caused by powder agglomeration would be generated prematurely during transportation,which seriously affected the stability of ceramic ink.In order to solve the above problems,a stable and homogeneous cobalt blue ceramic ink without insoluble particles was created by via of the reaction between inorganic salts and organic acids,forming water-soluble metal complex compound.The results of this paper are of great theoretical and practical significance for the development and application of ink-jet printing.Firstly,four alternative complexing agents(citric acid,ethylenediamine tetra acetic acid,acetylacetone and salicylic acid)were compared,and EDTA was selectively selected as the complexing agent.The results showed that the ink with EDTA had high stability,optimum rheological properties and the highest solubility of the complexed product(0.1mol/100ml).When 4g/100ml of PEG200 was added as a solubilizer,the solubility of the complexed product increased to 0.14mol/100ml.The stability of the ink was tested by a standing experiment,the result revealed that no precipitation or layering could be observed after 6 months of standing storage,indicating an extremely high stability of the ink.After calcining at high temperatures(800℃～1100℃),a series of pure(b value from50.42 to-17.59)and rich(a value from-19.02 to 7.76)blue pigments were prepared.With the increase of calcination temperature,the content of Co3O4 impuritie gradually decreased,the brightness of the pigment gradually increased.Furthermore,the value of B gradually decreased,and the color of the powder gradually became pure.With the decreased of cobalt content,the b value of the powder gradually increased,and the color changed from pale blue to bright blue.When the ink with the composition of A1:Co=2:0.85 was calcined at 1100℃,the optimum color performance was achieved(b value can reach-50.42).The zinc or chromium doped spinel-cobalt blue ceramic inks was prepared by complexation method,respectively.The results showed that with the increase of zinc content,a value of the pigment kept constant,b value gradually increased.Meanwhile,the yellow color tone in the powder body became stronger,and the pigment gradually changed from blue to cyan.With the increase of chromium content,a value of the pigment gradually increased,b value presented an opposite trend,corresponding to the color change from blue to cyan.Zn2+ and Cr3+ replaced Co2+ and Al3+ in the lattice,respectively,which changed the coordination state of Co2+,resulting in the introduction of cyan and greenish hue for the cobalt blue pigment.