A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall so as to surround a plurality of cells extending from a first end face to a second end face, and a circumferential coating layer composed of a circumferential coating material coated on at least a part of circumference of the honeycomb structure body, wherein the circumferential coating layer has a printing area for printing on the surface thereof, the printing area has a lightness (L*) in L*a*b* color space (CIE1976) defined by International Commission on Illumination (CIE) of 35 or more, and the printing area has a surface roughness Ra of 30 μm or less.

A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall so as to surround a plurality of cells extending from a first end face to a second end face, and a circumferential coating layer composed of a circumferential coating material coated on at least a part of circumference of the honeycomb structure body, wherein the circumferential coating layer has a printing area for printing on the surface thereof, the printing area has a lightness (L*) in L*a*b* color space (CIE1976) defined by International Commission on Illumination (CIE) of 35 or more, and the printing area has a surface roughness Ra of 30 μm or less.

A process for marking a surface of a refractory ceramic part, known as the “surface to be marked.” The part has a microstructure of grains including more than 50% by mass of ZrO.sub.2, bound by a silicate binder phase, and a total porosity of less than 5% by volume. The process involves irradiation of the surface with a laser beam. The beam is emitted by a laser device set to comply with relationship: a.V.sup.2+b.F.sup.2+c.VF+d.V+e.F+f<0, in which: a=10.sup.4.D+2×10.sup.6, b=0.5×10.sup.6.D−150×10.sup.6, c=0.5×10.sup.6.D−300×10.sup.6, d=5×10.sup.3.D−2.5×10.sup.6, e=−5×10.sup.3.D+2.0×10.sup.6, and f=−5×10.sup.9.D+1.8×10.sup.12. V is expressed in mm/second, D is expressed in mm and F is expressed in kHz.

A method of fabricating a grinding tool includes providing an abrasive particle, and cutting the abrasive particle with a laser beam so that the cut abrasive particle has four tips adjacent to one another, a cavity of a generally cross shape extending between the four tips, and a material discharge surface at an end of the cavity. The laser beam is applied along a plurality of parallel first cutting lines and a plurality of parallel second cutting lines, the second cutting lines intersecting the first cutting lines, at least the first cutting lines being grouped into a first, a second and a third region, the second region being located between the first and third regions, a number of cutting passes repeated along each of the first cutting lines in each of the first and third regions increasing as the first cutting line is nearer to the second region, and the laser beam repeating a plurality of cutting passes along each of the first cutting lines in the second region.

A process for treating a fused refractory product including more than 10% by mass of ZrO.sub.2, or “base product.” The process includes heating at least a portion of the surface of the product, so as to melt ZrO.sub.2 crystals in a superficial region extending to a depth of less than 2000 μm. The process includes cooling the molten superficial region obtained in the preceding step so as to obtain a protective layer.

A process for treating a fused refractory product including more than 10% by mass of ZrO.sub.2, or “base product.” The process includes heating at least a portion of the surface of the product, so as to melt ZrO.sub.2 crystals in a superficial region extending to a depth of less than 2000 μm. The process includes cooling the molten superficial region obtained in the preceding step so as to obtain a protective layer.

A cutting insert comprises: a body; and a blade fixed to the body and made of a polycrystalline cubic boron nitride including 98.5% by volume or more of cubic boron nitride, the blade having a rake face and a flank face, the rake face and the flank face meeting each other and thus forming a ridge line which serves as a cutting edge, the rake face being provided with a land surface extending along the cutting edge, and a chip breaker disposed on a side opposite to the cutting edge with the land surface therebetween and also having a recess contiguous to the land surface.

A cutting insert comprises: a body; and a blade fixed to the body and made of a polycrystalline cubic boron nitride including 98.5% by volume or more of cubic boron nitride, the blade having a rake face and a flank face, the rake face and the flank face meeting each other and thus forming a ridge line which serves as a cutting edge, the rake face being provided with a land surface extending along the cutting edge, and a chip breaker disposed on a side opposite to the cutting edge with the land surface therebetween and also having a recess contiguous to the land surface.

A method for etching a light absorbing material permits directly writing a pattern of etching of silicon nitride and other light absorbing materials, without the need of a lithographic mask, and allows the creation of etched features of less than one micron in size. The method can be used for etching deposited silicon nitride films, freestanding silicon nitride membranes, and other light absorbing materials, with control over the thickness achieved by optical feedback. The etching is promoted by solvents including electron donor species, such as chloride ions. The method provides the ability to etch silicon nitride and other light absorbing materials, with fine spatial and etch rate control, in mild conditions, including in a biocompatible environment. The method can be used to create nanopores and nanopore arrays.

A method for etching a light absorbing material permits directly writing a pattern of etching of silicon nitride and other light absorbing materials, without the need of a lithographic mask, and allows the creation of etched features of less than one micron in size. The method can be used for etching deposited silicon nitride films, freestanding silicon nitride membranes, and other light absorbing materials, with control over the thickness achieved by optical feedback. The etching is promoted by solvents including electron donor species, such as chloride ions. The method provides the ability to etch silicon nitride and other light absorbing materials, with fine spatial and etch rate control, in mild conditions, including in a biocompatible environment. The method can be used to create nanopores and nanopore arrays.