Ceramics-coated heat resisting alloy member

A gas turbine bucket applied with a ceramic coating comprising:

• a base material of said bucket made of a heat resisting alloy the main component of which is selected from at least one of nickel, cobalt and iron;
• and
• a plurality of coating layers for the front portion of said bucket which is applied to a region extending from the leading edge of said bucket to the suction surface and the pressure surface of said bucket in substantially a quarter length of the overall length of the profile of said bucket;
• said plurality of coating layers for the front portion consisting of:
• a first alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said base material;
• a mixture layer which comprises a ceramic material and a metal and which is formed on said first alloy layer;
• a second alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said mixture layer;
• and
• a ceramic layer which comprises a ceramic material and which is formed on said second alloy layer,
• said ceramic material of said ceramic layer comprising ZrO.sub.2 as a main component and at least one of CaO, Y.sub.2 O.sub.3 and MgO.

A gas turbine bucket applied with a ceramic coating comprising:

• a base material of said bucket made of a heat resisting alloy the main component of which is selected from at least one of nickel, cobalt and iron;
• a plurality of coating layers for the front portion of said bucket which is applied to a region extending from the leading edge of said bucket to the suction surface and the pressure surface of said bucket in substantially a quarter length of the overall length of the profile of said bucket;
• and
• a coating layer for the rear portion which is applied to the surface of said bucket except for said region,
• said plurality of coating layers for said front portion consisting of:
• a mixture layer which comprises a ceramic material and metal and which is formed on said base material of said bucket;
• a first alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said mixture layer;
• a ceramic layer which comprises a ceramic material and which is formed on said first alloy layer,
• said ceramic material of said ceramic layer comprising ZrO.sub.2 as a main component and at least one of CaO, Y.sub.2 O.sub.3 and MgO;
• and
• said coating layer for the rear portion consisting of:
• a second alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said base material of said bucket;
• wherein the thickness of said coating layer for said rear portion is smaller than that for said front portion and successively formed.

A gas turbine bucket applied with a ceramic coating comprising:

• a base material of said bucket made of a heat resisting alloy the main component of which is selected from at least one of nickel, cobalt and iron;
• a plurality of coating layers for the front portion of said bucket which is applied to a region extending from the leading edge of said bucket to the suction surface and the pressure surface of said bucket in substantially a quarter length of the overall length of the profile of said bucket;
• and
• a plurality of coating layers for the rear portion which is applied to the surface of said bucket except for said region,
• said plurality of coating layers for said front portion consisting of:
• a first alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on the surface of said base material of said bucket;
• a mixture layer which comprises a ceramic material and metal and which is formed on said first alloy layer;
• a second alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said mixture layer;
• and
• a first ceramic layer which comprises a ceramic material and which is formed on said second alloy layer;
• and
• said plurality of coating layers for said rear portion consisting of:
• a third alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on the surface of said base material of said bucket;
• and
• a second ceramic layer which comprises a ceramic material and which is formed on said third alloy layer,
• said ceramic material of said first and second ceramic layers comprising ZrO.sub.2 as a main component and at least one of CaO, Y.sub.2 O.sub.3 and MgO;
• wherein the thickness of said coating layer for said rear portion is smaller than that for said front portion and is successively formed.

A gas turbine nozzle applied with a ceramic coating comprising:

• a base material of said nozzle made of a heat resisting alloy the main component of which is selected from at least one of nickel, cobalt and iron;
• a plurality of coating layers for the front portion of said nozzle which is applied to a region extending from the leading edge of said nozzle to the suction surface and the pressure surface of said nozzle in substantially a quarter length of the overall length of the profile of said nozzle;
• and
• a coating layer for the rear portion which is applied to the surface of said nozzle except for said region,
• said plurality of coating layers for said front portion consisting of:
• a mixture layer which comprises a ceramic material and metal and which is formed on said base material of said nozzle;
• a first alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said mixture layer;
• a ceramic layer which comprises a ceramic material and which is formed on said third alloy layer,
• said ceramic material of said ceramic layer comprising ZrO.sub.2 as a main component and at least one of CaO, Y.sub.2 O.sub.3 and MgO;
• and
• said coating layer for said rear portion consisting of:
• a second alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said base material of said nozzle;
• wherein the thickness of said coating layer for said rear portion is smaller than that for said front portion and successively formed.

A gas turbine nozzle applied with a ceramic coating comprising:

• a base material of said nozzle made of a heat resisting alloy the main component of which is selected from at least one of nickel, cobalt and iron;
• a plurality of coating layers for the front portion of said nozzle which is applied to a region extending from the leading edge of said nozzle to the suction surface and the pressure surface of said nozzle in substantially a quarter length of the overall length of the profile of said nozzle;
• and
• a plurality of coating layers for the rear portion which is applied to the surface of said nozzle except for said region,
• said plurality of coating layers for said front portion consisting of:
• a first alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on the surface of said base material of said nozzle;
• a mixture layer which comprises a ceramic material and metal and which is formed on said first alloy layer;
• a second alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on said mixture layer;
• a first ceramic layer which comprises a ceramic material and which is formed on said second alloy layer,
• said ceramic material of said first ceramic layer comprising ZrO.sub.2 as a main component and at least one of CaO, Y.sub.2 O.sub.3 and MgO;
• and
• said plurality of coating layers for said rear portion consisting of:
• a third alloy layer which comprises an alloy material superior to said base material with respect to its resistance to high temperature oxidation and resistance to high temperature corrosion and which is formed on the surface of said base material of said nozzle;
• and
• a second ceramic layer which comprises a ceramic material and which is formed on said third alloy layer wherein the thickness of said coating layer for said rear portion is smaller than that for said front portion and successively formed.

A gas turbine bucket applied with a ceramic coating comprising:

• a base material of said bucket made of a heat resisting alloy;
• a plurality of coating layers for the front portion of said bucket which is applied to a region extending from the leading edge of said bucket to the suction surface and the pressure surface of said bucket in substantially a quarter length of the overall length of the profile of said bucket;
• and
• a plurality of coating layers for the rear portion which is applied to the surface of said bucket except for said region,
• said plurality of coating layers for said front portion consisting of:
• a first alloy layer which comprises an alloy material and which is formed on the surface of said base material by a spray coating method;
• a mixture layer which comprises a ceramic material and metal in a ratio by weight of 1:1 and which is formed on said first alloy layer by a spray coating method;
• a second alloy layer which comprises an alloy material and which is formed on said mixture layer by a spray coating method;
• and
• a first ceramic layer which comprises a ceramic material and which is formed on said second alloy layer by a spray coating method;
• and
• said plurality of coating layers for said rear portion consisting of:
• a third alloy layer which comprises an alloy material and which is formed on the surface of said base material by a spray coating method;
• and
• a second ceramic layer which comprises a ceramic material and which is formed on said third alloy layer by a spray coating method, wherein
• the thickness of said coating alyers for said rear portion is smaller than that for said front portion and successively formed, and wherein
• said heat resisting alloy of base material comprises at least one of Ni and Co as a main component, 7 to 20 wt % of Cr and 1 to 8 wt % of at least one of Ti and A1, and at least one of Ta, Nb, W and Mo in a total content of 10 wt % or less;
• said alloy material of said first, second and third alloy layers comprises at least one of Ni and Co, 13 to 40 wt % of Cr, 5 to 20 wt % of A1, and 0.1 to 3 wt % of at least one of Hf, Ta, Y, Si and Zr;
• said ceramic material of said first and second ceramic layers comprises ZrO.sub.2 as a main component, and at least one of 4 to 20 wt % of Y.sub.2 O.sub.3, 4 to 8 wt % of CaO and 4 to 24 wt % of MgO;
• the thickness of each of said alloy layers is 0.1 mm;
• the thickness of said mixture layer is 0.3 mm;
• the thickness of each of said ceramic layers is 0.4 mm;
• and
• said spray coating method is a plasma spray coating method.