Glass ceramic toughened with tetragonal zirconia

Patent · Tue Dec 31 23:00:00 EST 1985

OSTI ID:865843

Keefer, Keith D ^[1]; Michalske, Terry A ^[2]

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1. Albuquerque, NM
2. Sandia Park, NM

A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat-treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nucleating agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200.degree. to 1700.degree. C. and is then heat-treated at a temperature within the range of 800.degree. to 1200.degree. C. in order to precipitate tetragonal ZrO.sub.2. The composition, as well as the length and temperature of the heat-treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.

• Research Organization: AT & T CORP
• DOE Contract Number: AC04-76DP00789
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4587224
• OSTI ID: 865843
• Country of Publication: United States
• Language: English

Related Subjects

/501/
1200
1700
800
added
agents
ambient
ambient temperature
appreciable
carefully
carefully controlled
ceramic
composition
controlled
conversion
degree
disclosed
facilitate
form
glass
glass ceramic
heat-treated
heat-treatment
heated
homogeneous
homogeneous melt
improve
length
melt
melted
mixture
monoclinic
monoclinic phase
network-forming
network-modifying
nucleating
nucleating agent
nucleating agents
oxide
particulate
phase
phase transformation
precipitate
precipitated
preferably
prevent
process
processing
properties
quantity
range
retained
solution
stabilizing
stabilizing agent
subsequent
temperature
tetragonal
tetragonal zro
toughened
transformation-toughened
yield
zirconia
zirconium
zirconium oxide
zro