Plating or Coating Method for Producing Metal-Ceramic Coating on a Substrate

Abstract

A plating or coating method for producing a metal-ceramic composite coating on a substrate is provided. The method N comprises adding a sol of a ceramic phase to a plating solution or electrolyte and controlling the pH, degree of mixing, and/or temperature of the plating solution or electrolyte. An item or surface comprising a substrate and a metal-ceramic composite coating on the substrate, the metal-ceramic composite coating comprising a ceramic phase of dispersed amorphous ceramic particles having an average diameter of from 1 to 100 nm is also provided.

1 . A plating or coating method for producing a metal-ceramic composite coating on a substrate, the method comprising adding a sol of a ceramic phase to a plating solution or electrolyte, and controlling the pH, degree of mixing, and/or temperature of the plating solution or electrolyte to reduce or prevent the precipitation of visible particles and/or agglomerates of the ceramic phase in the plating solution or electrolyte. 
     
     
         2 . A plating or coating method according to  claim 1 , wherein the pH, degree of mixing, and/or temperature is controlled such that the metal-ceramic coating forms on the substrate with a predominantly crystalline structure. 
     
     
         3 . A plating or coating method according to  claim 1  or  2 , wherein the pH, degree of mixing, and/or temperature is controlled to reduce or prevent the formation of particles and/or agglomerates of particles of the ceramic phase having an average diameter more than 100 nm in the plating solution or electrolyte. 
     
     
         4 . A plating or coating method according to any one of  claims 1  to  3 , wherein the pH, degree of mixing, and/or temperature is controlled such that amorphous particles of the ceramic phase having an average diameter from about 1 to about 100 nm are incorporated into the metal-ceramic composite coating. 
     
     
         5 . A plating or coating method according to  claim 4 , wherein the amorphous particles are dispersed throughout the metal-ceramic composite coating. 
     
     
         6 . A plating or coating method according to any one of  claims 1  to  5 , wherein the pH of the plating solution or electrolyte is monitored. 
     
     
         7 . A plating or coating method according to any one of  claims 1  to  6 , wherein the pH of the plating solution or electrolyte is maintained within a predetermined pH range during addition of the sol. 
     
     
         8 . A plating or coating method according to any one of  claims 1  to  7 , wherein the pH, degree of mixing, and/or temperature of the plating solution or electrolyte is controlled during plating or coating of the substrate. 
     
     
         9 . A plating or coating method according to any one of  claims 1  to  8 , further comprising controlling the rate of sol addition to the plating solution or electrolyte. 
     
     
         10 . A plating or coating method according  claim 9  comprising adding the sol at a rate of less than about 0.02 ml per second/litre of the plating solution or electrolyte. 
     
     
         11 . A plating or coating method according to any one of  claims 1  to  10 , wherein the sol has a sol concentration of 10 to 400 grams of the ceramic phase per litre of the sol. 
     
     
         12 . A plating or coating method according to  claim 11  comprising adding the sol at a rate of 0.5 to 250 mls of sol per litre of the plating solution. 
     
     
         13 . A plating or coating method according to any one of  claims 1  to  12 , comprising producing at least one additional coating on the substrate prior to or after producing the metal-ceramic composite coating. 
     
     
         14 . A plating or coating method according to any one of  claims 1  to  13 , wherein the ceramic phase is a single or mixed oxide, carbide, nitride, silicate, boride of Ti, W, Si, Zr, Al, Y, Cr, Fe, Pb, Co, or a rare earth element. 
     
     
         15 . A plating or coating method according to any one of  claims 1  to  14 , wherein the ceramic phase comprises TiO 2 , AlO 2 , Al 2 O 3 , ZrO 2 , SiC, SiO 2 , SiC, CeO 2 , or ZnO. 
     
     
         16 . A plating or coating method according to any one of  claims 1  to  15 , wherein the coating, other than the ceramic phase comprises a metal or metalloid selected from Zn, Cd, Cu, Ni, Cr, Sn, Au, Ag, Pb, Ru, Rh, Pd, Os, Ir, Fe, Co, In, As, Sb, Bi, Mn, Re, Al, Zr, Ti, Hf, V, Nb, Ta, W, and Mo, or an alloy of any two or more thereof. 
     
     
         17 . A plating or coating method according to any one of  claims 1  to  16  wherein the coating, other than the ceramic phase comprises Ni, Ni—P, Ni—W—P, Ni—Cu—P, Ni—B, Au—Ni, Ni—Zn, Ni—Co, Ni—W, Ni—Fe, Cr, Cu, Zn, Ag, Au, or Pd. 
     
     
         18 . A plating or coating method according to any one of  claims 1  to  17 , wherein the metal-ceramic composite coating comprises Au—Ni—TiO 2 , Ni—Co—TiO 2 , Ni—Zn—Al 2 O 3 , or Ni—B—TiO 2 . 
     
     
         19 . A plating or coating method according to any one of  claims 1  to  18 , wherein the metal-ceramic composite coating comprises Ni—Co—TiO 2  or Ni—Zn—Al 2 O 3 . 
     
     
         20 . A plating or coating method according to any one of  claims 1  to  17 , wherein the metal-ceramic composite coating comprises Ni—P—ZrO 2 , the additional coating comprises Ni—P, and the additional coating is produced prior to producing the metal-ceramic composite coating. 
     
     
         21 . A plating or coating method according to any one of  claims 1  to  17 , wherein the metal-ceramic composite coating comprises Ag—TiO 2 . 
     
     
         22 . A plating or coating method according to any one of  claims 1  to  21  wherein the substrate is a metal substrate, plastics or ceramic substrate. 
     
     
         23 . A plating or coating method according to any one of  claims 1  to  22  which is an electroless plating or coating process, wherein the solution comprises as a reducing agent sodium hypophosphite, sodium borohydride, formaldehyde, dextrose, rochelle salts, glyoxal, or hydrazine sulfate. 
     
     
         24 . A plating or coating method according to any one of  claims 1  to  22  which is a galvanic plating process wherein the plating current is in the range 5 mA/cm 2  to 300 mA/cm 2 . 
     
     
         25 . An item or surface comprising a substrate and a metal-ceramic composite coating on the substrate, the metal-ceramic composite coating comprising a ceramic phase of dispersed amorphous ceramic particles having an average diameter of from 1 to 100 nm. 
     
     
         26 . The item or surface according to  claim 25 , wherein the item or surface comprises at least one additional coating under or on top of the metal ceramic coating.