Pistons with thermal barrier coatings
A method of making a piston for an opposed-piston engine comprises providing a piston. The piston comprises a substantially cylindrical portion including a sidewall and a piston crown located at an end of the piston. The piston crown comprises an end surface structured to form a combustion chamber when disposed within a cylinder bore in cooperation with an end surface of a cooperating opposing piston. A bonding layer including a bonding material is deposited on the end surface of the piston crown using a high velocity oxy-fuel spray process. At least one thermal barrier layer comprising ceramic material is deposited above the bonding layer.
1. A method of making a piston for an opposed-piston engine, the method comprising:
providing a piston, the piston comprising a piston crown located at an end of the piston, the piston crown comprising:
a cylindrical portion including a sidewall; and
an end surface structured to form a combustion chamber when disposed within a cylinder bore in cooperation with an end surface of a cooperating opposing piston;
masking a portion of the end surface;
depositing a bonding layer including a bonding material on the end surface of the piston crown;
unmasking the portion of the end surface;
depositing the bonding layer on at least the portion of the end surface for a first predetermined time; and
depositing at least one thermal barrier layer comprising ceramic material above the bonding layer.
2. The method of claim 1 , wherein the at least one thermal barrier layer is deposited using an atmospheric plasma spray.
3. The method of claim 2 , wherein depositing at least one thermal barrier layer comprises ceramic material above the bonding layer comprises depositing a plurality of thermal barrier sublayers, each of the plurality of thermal barrier sublayers including a proportion of the ceramic material and a proportion of the bonding material, wherein the proportion of the ceramic material decreases and the proportion of the bonding material increases with the depth of the thermal barrier layer.
4. The method of claim 3 , wherein depositing a plurality of thermal barrier sublayers comprises depositing at least one sublayer of the plurality of thermal barrier sublayers with a thickness that is different from a thickness of another sublayer of the plurality of thermal barrier sublayers.
5. The method of claim 2 , wherein depositing at least one thermal barrier layer comprises ceramic material above the bonding layer comprises depositing a ceramic material including at least one of yttria stabilized zirconia, mullite, alumina, and rare-earth zirconates.
6. The method of claim 5 , wherein the ceramic material comprises yttria stabilized zirconia in a range of 7 wt % to 9 wt %.
7. The method of claim 2 , wherein the at least one thermal barrier layer is deposited using a plurality of the atmospheric plasma spray.
8. The method of claim 2 , wherein providing a piston comprises providing the piston where the end surface comprises at least one of steel, aluminum alloy, titanium, a titanium alloy, or a nickel alloy.
9. The method of claim 1 , wherein the bonding material is deposited using a high velocity oxy-fuel spray.
10. The method of claim 9 , wherein depositing the bonding layer comprises providing a plurality of line passes of the high velocity oxy-fuel spray.
11. The method of claim 1 , further comprising:
masking the portion of the end surface before depositing the at least one thermal barrier material comprising ceramic material above the bonding material; and
unmasking the portion of the end surface; and
depositing the at least one thermal barrier comprising ceramic material over the bonding layer coated on the portion of the end surface for a second predetermined time.