Developments in Ceramic Materials Research

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Dena Rosslere
times of stress, people used pottery to help identify themselves as part of a cohesive
sociopolitical group.
Chapter 2 - Rotary ultrasonic machining (RUM) is one of the nontraditional machining
processes for ceramics. This chapter overviews the recent advances in RUM of ceramics since
2001. It first reports the progress on quality improvement of RUM machined parts – reduction
and elimination of edge chipping in RUM of ceramics. After discussing the effects of RUM
process parameters (spindle speed, feedrate, ultrasonic vibration power, and grit size) on the
edge chipping thickness, practical ways to reduce the edge chipping are presented.
It then presents recent studies on the effects of coolant type, pressure, and delivery mode
(continuous versus intermittent) on cutting force and surface roughness when RUM of
ceramics.
Finally, it reports the exploratory efforts to apply RUM to machine silicon carbide and
ceramic matrix composites (CMC). It discusses the effects of RUM process parameters
(spindle speed, feedrate, ultrasonic vibration power, and grit size etc.) on cutting force,
surface roughness, tool wear, and chipping size.
Chapter 3 - Laser oxide ceramics (Y3Al5O12, Y2O3, etc. doped with Nd 3+ , Yb 3+ , etc.) is
the most serious innovation of last years in the field of laser materials.
However, the chapter summarizes new efforts of General Physics Institute of Russian
Academy of Sciences, Moscow and State Optical Institute, S.-Petersburg for the research and
development of optical ceramics of two other classes of chemical compounds: fluorides and
oxysulfides.
The technique of preparation and results of study of a structure of ceramic samples as
well as its mechanical, thermal, optical and fluorescence properties is reported.
The analysis of development tendencies in modern photonics shows that recent progress
in the area relates substantially with the devices based on the fluoride optical ceramics due to:
• wide spectral transparency window from 0.16 to 11 microns and low phonon
spectra preventing from strong fluorescence quenching by the multiphonon
relaxation of radiative transitions of impurity ions;
• long lifetimes of metastable levels;
• ease of high level doping of the ceramic host by rare-earth ions (up to 10 21 cm -3 );
• excellent mechanical properties, e.g. the CaF2 optical ceramics, both natural and
artificial, has anomalously high fracture toughness, which is three - six fold
higher than that for single fluoride crystals;
• high moisture resistance compared to other classes of optical materials with a
wide spectral transmission window;
• high thermal conductivity;
• low level of optical losses in ceramic samples, about 10 -2 - 10 -3 cm -1 in one
micron spectral range.
The material properties of natural CaF2 optical nanoceramics (Suran Deposit, South Ural)
as a model object is discussed first. Then the technology development of preparation of
synthetic optical fluoride ceramics of different chemical composition is introduced starting
from a nanotechnology of preparation of initial raw materials. After that the material
properties and advantages of artificial fluoride optical ceramics versus the fluoride single