초록 ▼

In the encapsulation of insert materials within glass and glass-ceramic articles, not only must the bonding characteristics between the insert and the glass or glass-ceramic materials be considered, but also the relative coefficient of thermal expansions between the insert and the encapsulating mate

In the encapsulation of insert materials within glass and glass-ceramic articles, not only must the bonding characteristics between the insert and the glass or glass-ceramic materials be considered, but also the relative coefficient of thermal expansions between the insert and the encapsulating materials must be programmed in order to avoid undue stresses in the article or the insert which could produce deleterious results.

대표청구항 ▼

A method of forming a composite glass-ceramic cooking vessel having a heat conducting insert fully encapsulated therewithin which comprises, supplying molten glass having a first coefficient of thermal expansion, supplying a heat conducting insert which does not chemically or fusion bond to the molt

A method of forming a composite glass-ceramic cooking vessel having a heat conducting insert fully encapsulated therewithin which comprises, supplying molten glass having a first coefficient of thermal expansion, supplying a heat conducting insert which does not chemically or fusion bond to the molten glass and which has a second coefficient of thermal expansion which is less than 20×10-7/°C. greater than the first coefficient of thermal expansion of the molten glass, fully encapsulating said insert within said molten glass, cooling said molten glass and the encapsulated insert to form a composite glass article having an insert fully encapsulated therewithin, contracting the insert upon cooling at a greater rate than that of the glass during said cooling, subjecting the composite article to elevated temperatures and converting the glass to a glass-ceramic article, shrinking the glass-ceramic article while at elevated temperatures about said insert and simultaneously inducing stress in said article, and cooling said composite glass-ceramic article to room temperature while simultaneously contracting said insert at a greater rate than that of said glass-ceramic article and thereby relieving the stress induced in said article to form a glass-ceramic cooking vessel having a heat conducting insert fully encapsulated therewithin. An integral glass-ceramic article for supporting material to be heated having an insert fully encapsulated therewithin which comprises, an integral body portion of glass-ceramic material having a first coefficient of thermal expansion and a first modulus of elasticity, a heat-conductive graphite insert fully embedded within said glass-ceramic article having a second coefficient of thermal expansion greater than said first coefficient of thermal expansion and a second modulus of elasticity less than said first modulus of elasticity, said coefficient of thermal expansion of said graphite insert being selected so that said graphite insert is in intimate contact with said glass-ceramic body at room temperature without exerting undesirable stresses therebetween, and said graphite insert providing improved heat transfer within said glass-ceramic article upon application of heat to said article.