A vacuum insulated structure for use in an appliance includes an inner liner and an outer wrapper coupled to the inner liner. A vacuum insulated cavity is defined therebetween. An insulation material is disposed in the vacuum insulated cavity. The insulation material includes porous glass flakes.

A vacuum insulated structure for use in an appliance includes an inner liner and an outer wrapper coupled to the inner liner. A vacuum insulated cavity is defined therebetween. An insulation material is disposed in the vacuum insulated cavity. The insulation material includes porous glass flakes.

A method of forming an insulation material for a vacuum insulated structure includes heating glass flakes to at least a glass transition temperature of the glass flakes to induce a phase separation of the glass into an acid insoluble silica phase and an acid soluble phase. The glass flakes can be derived from a glass composition containing (by weight): SiO.sub.2 from about 40% to about 80%, B.sub.2O.sub.3 from about 10% to about 40%, Na.sub.2O from about 1% to about 10%, Li.sub.2O from about 0% to about 3%, CaO from about 0% to about 10%, ZnO from about 0% to about 5%, P.sub.2O.sub.5 from about 0% to about 10%, and Al.sub.2O.sub.3 from about 0% to about 10%. The method also includes a step of etching the glass flakes to dissolve the acid soluble phase to form porous glass flakes.

A body, such as a lamp body, includes a tubular element. At least one conductor is introduced into the tubular element and a glass material surrounds the conductor. The glass material forms a seal between the tubular element and the conductor. The glass material includes a sintered glass, such as a sintered glass ring, and may completely surround the conductor.

To provide an opaque quartz glass having excellent heat insulating property, mechanical strength and surface smoothness, a silica powder water slurry of concentration of 45 to 75 wt % is subjected to wet pulverization with silicon nitride beads having a mean diameter of 0.1 mm to 3 mm. The silica powder and silicon nitride beads are subjected to abrasion and the silicon nitride powder works as foaming agent and independent spherical bubbles are formed for manufacturing opaque quartz glass which has air cells having a mean diameter of 2 to 30 m and are independent spherical, having a density of 1.90 to 2.20 g/cm.sup.3, a whiteness of 80 or more, a reflectance of 80% or more for light of a wavelength of 0.2 to 3 m at thickness of 3 mm, a bending strength of 70 MPa or more, a surface roughness Ra of the baked surface of 0.7 m or less.

A body, such as a lamp body, includes a tubular element. At least one conductor is introduced into the tubular element and a glass material surrounds the conductor. The glass material forms a seal between the tubular element and the conductor. The glass material comprises a sintered glass, such as a sintered glass ring, and may completely surround the conductor.

To provide opaque quartz glass having no water absorbing properties and being excellent in infrared light shielding properties, and a method for its production. In the production of opaque quartz glass of the present invention, a fine amorphous silica powder and a pore forming agent are mixed, then molded and heated at a predetermined temperature, to obtain opaque quartz glass wherein contained pores are closed pores, the average pore size of pores is from 5 to 20 m, and the content density of pores is high, whereby the heat shielding properties are high.

To provide opaque quartz glass having no water absorbing properties and being excellent in infrared light shielding properties, and a method for its production. In the production of opaque quartz glass of the present invention, a fine amorphous silica powder and a pore forming agent are mixed, then molded and heated at a predetermined temperature, to obtain opaque quartz glass wherein contained pores are closed pores, the average pore size of pores is from 5 to 20 m, and the content density of pores is high, whereby the heat shielding properties are high.