SPI Supplies Brand All Ceramic Tweezers Straight Smooth Precision Tip 125 mm Long
Straight, smooth, Precision tip
Length: 125 mm
These hi-tech tweezers have tips made of solid ceramic that makes them ideal for use in the semiconductor industry, clean-rooms, bio-technology and analytical chemistry, analytical chemistry, and microscopy.
Zirconia fine ceramic is an extraordinarily hard material, however, any material this hard also has some brittle nature to it as well. Hence one must use great care in how these tweezers are used, since the tips, while being more robust than stainless steel, are nevertheless fragile and can be broken without too much difficulty.
The solid zirconia ceramic construction produces a tweezer with an outstanding "feel" and is preferred for really high precision work over just about any other kind of tweezer, especially when high chemical resistance or complete freedom from any magnetism whatsoever is required.
Some other advantages of the all ceramic tweezers, which might not be immediately obvious, would include the fact that the ceramic is highly resistant to static charging, therefore these tweezers are much less likely to be attracting dust particles from the air. About the only chemical that will attack this particular ceramic is HF. And while these ceramic tweezers will not last forever, they will last much longer than metal tweezers being used in the same kind of application.
Soft and silver solder will not adhere to the ceramic tips or surface.
Temperature range of use:
The melting point is well over 2000°C, however when one is contemplating the temperature range of use, it is more complicated.
The ceramic, so far as ceramics are concerned, is quite strong. However, there is a close relationship between the strength of the ceramic and the crystal form of the zirconia. And while is it something not generally appreciated, both temperature as well as applied force can cause the crystal phases to transform to less desirable crystal structures.
The zirconia could have three different crystalline phases:
- Monoclinic: Stable under 1100°C
- Tetragonal: Stable between 1100-1600°C
- Cubic: Stable above 1600°C
The point is that due to the added yttria, the tetragonal phase now becomes stable at room temperature. But when force is applied, such as a bending motion, this room-temperature stable phase can transform back to the monoclinic phase (and with an associated volume expansion). This is the model as to why yttria toughened zirconia has such high strength at room temperature, because the volume expansion tends to fill cracks caused by the applied force. However, when the yttria toughened zirconia is annealed above annealing in above 200°C, many tetragonal regions transform to the monoclinic form. And after this transformation, when force is applied, you don't have the toughening mechanism operating, so after annealing, the ceramic has lost at least some of its original strength by an estimated about of 50% when compared to it strength at room temperature without annealing.
Therefore, this is why recommend that the tweezers not be used above 200°C if it is important to retain the original room temperature properties. Over 200°C, the tweezers don't just "fall apart" but they do have reduced strength properties, but could nevertheless be used at far higher temperatures, so long as this loss of some of its strength is understood.
Useful lifetime expectancy:
The lifetime any one user will experience will depend on what is being picked up and how carefully the tweezers are being used. In general, the ceramic tweezers should last quite some time in comparison to metal tweezers with tips that can be easily misaligned.