Coating processes with a polycrystalline diamond passivation layer

Abstract

A process for minimizing or avoiding the corrosion of thermal ink jet heater components by the coating thereof with polycrystalline diamond.

What is claimed is: 
     
       1. A process for minimizing or avoiding the corrosion of thermal ink jet heater components consisting essentially of accomplishing the coating of said components with a polycrystalline diamond passivation layer, and wherein said polycrystalline diamond contains a peak at 1,330 cm -1  in the Raman spectra. 
     
     
       2. A process in accordance with claim 1 wherein there is selected a plasma deposited thermally conducting polycrystalline diamond. 
     
     
       3. A process in accordance with claim 1 wherein the corrosion of ink jet heaters is avoided for extended time periods. 
     
     
       4. A process in accordance with claim 2 wherein the polycrystalline diamond layer is of a thickness of from about 0.2 to about 10 microns. 
     
     
       5. A process in accordance with claim 3 wherein the polycrystalline diamond layer is of a thickness of from about 0.2 to about 10 microns. 
     
     
       6. A process which comprises the growth of a continuous polycrystalline diamond film over a silicon wafer contained on thermal ink jet heaters by means of a hot filament assisted chemical vapor deposition which decomposes hydrogen and carbon containing gases in a processing apparatus; followed by etching the diamond film obtained in a pattern in a reactive ion etch processing apparatus using an aluminum mask and oxygen gas decomposed by a rf plasma, and wherein said diamond film contains a peak at 1,330 cm -1  in the Raman spectra. 
     
     
       7. A process in accordance with claim 2 wherein the polycrystalline diamond contains from about 0.1 weight percent to about 1 weight percent of hydrogen. 
     
     
       8. A process in accordance with claim 3 wherein the polycrystalline diamond contains from about 0.1 weight percent to about 1 weight percent of hydrogen. 
     
     
       9. A process in accordance with claim 2 wherein the polycrystalline diamond selected possess an electrical conductivity of 10 -8  (ohm-cm) -1 . 
     
     
       10. A process in accordance with claim 3 wherein the polycrystalline diamond selected possess an electrical conductivity of 10 -8  (ohm-cm) -1 . 
     
     
       11. A process in accordance with claim 1 wherein the coating is of a thickness of from about 2,000 Angstroms to about 10 microns. 
     
     
       12. A process in accordance with claim 1 wherein the coating is of a thickness of from about 2,000 Angstroms to about 10 microns. 
     
     
       13. A process in accordance with claim 2 wherein the coating is of a thickness of from about 2,000 Angstroms to about 10 microns. 
     
     
       14. A process for minimizing the corrosion of thermal ink jet heaters consisting essentially of coating said ink jet heater with a thermally conducting polycrystalline diamond passivation layer, which layer is situated between the thermal ink jet heater and the ink jet composition selected for ink jet printing.