Refractory mass and particles mixture for forming a refractory mass

The mixture of particles for use in a ceramic welding process for forming a coherent refractory mass on a surface by projecting against that surface the mixture and oxygen, the mixture comprising:

• refractory particles;
• fuel particles capable of reacting in an exothermic manner with oxygen to release sufficient heat to melt at least the surfaces of the refractory particles for forming the coherent refractory mass, which fuel particles are finely divided particles having a mean grain size of less than 50 .mu.m and are comprised of at least one element which is oxidisable to form a refractory oxide and is selected from the group consisting of silicon, aluminum, and magnesium;
• and
• carbonaceous particles having a mean grain size in excess of 0.5 mm, which carbonaceous particles are of such a size or composition that, when the mixture is projected against the surface in the presence of oxygen under conditions which lead to substantially complete oxidation of the fuel particles and the formation of the coherent refractory mass, the carbonaceous particles will not be completely oxidized, whereby carbon particles become occluded in the coherent refractory mass formed.

A mixture of particles for use in a ceramic welding process for forming a coherent refractory mass on a surface by projecting against that surface the mixture and oxygen, the mixture comprising:

• refractory particles;
• fuel particles, which fuel particles are capable of reacting in an exothermic manner with oxygen to release sufficient heat to melt at least the surfaces of the refractory particles for forming the coherent refractory mass and which fuel particles are finely divided particles having a mean grain size of less than 50 .mu.m and are comprised of at least one element which is oxidizable to form a refractory oxide and is selected from the group consisting of silicon, aluminum, and magnesium;
• and
• carbonaceous particles, which carbonaceous particles are of such a size or composition that, when the mixture is projected against the surface in the presence of oxygen, under conditions which lead to substantially complete oxidation of the fuel particles and the formation of the coherent refractory mass, the carbonaceous particles will not be completely oxidized, whereby carbon particles become occluded in the coherent refractory mass formed,
• wherein each of the carbonaceous particles is comprised of a core of carbonaceous material and a mantle comprised of a material which inhibits oxidation of the core, the mantle covering the core.

A mixture of particles for use in a ceramic welding process for forming a coherent refractory mass on a surface by projecting against that surface the mixture and oxygen, the mixture comprising:

• refractory particles;
• fuel particles, which fuel particles are capable of reacting in an exothermic manner with oxygen to release sufficient heat to melt at least the surfaces of the refractory particles for forming the coherent refractory mass and which fuel particles are finely divided particles having a mean grain size of less than 50 .mu.m and are comprised of at least one element which is oxidizable to form a refractory oxide and is selected from the group consisting of silicon, aluminum, and magnesium;
• and
• carbonaceous particles, which carbonaceous particles are of such a size or composition that, when the mixture is projected against the surface in the presence of oxygen, under conditions which lead to substantially complete oxidation of the fuel particles and the formation of the coherent refractory mass, the carbonaceous particles will not be completely oxidized, whereby carbon particles become occluded in the coherent refractory mass formed,
• wherein the mixture further comprises further particles comprising at least one element which is oxidizable to form a refractory oxide, which further particles are of such a size or composition that, when the mixture is projected against the surface in the presence of oxygen and under conditions which lead to substantially complete oxidation of the fuel particles and the formation of the coherent refractory mass, such further particles will not be completely oxidized, whereby unoxidized portions of the further particles become occluded in the refractory mass, and
• wherein the further particles comprise a core comprised of the at least one element which is oxidizable to form a refractory oxide and a mantle comprised of a material which inhibits oxidation of the core, which mantle covers the core.