PT Labware

Our labware has been manufactured by skilled craftsman possessing many years of experience. A key part of our success in this area has been our continual quality improvement process where our products undergo stringent inspection and control checks.

Metallurgy of Platinum Laboratory Apparatus

Platinum is the metal most widely used in the manufacture of labware but other noble metals are often alloyed with platinum to provide certain desirable properties or adwantages.

The most common alloy combinations available are:

– Platinum

Pure platinum has been shown over many decades to be superior to any of its alloys with other elements min the noble metals group in its resistance to the action of acids and fusion mixtures.
LA platinum is the standard material used for the bulk of laboratory apparatus. This Contains deliberate small additions of iridium and rhodium which strengthen the platinum to give it more durability. The platinum content of LA platinum is 99.7% minimum.

– Rhodium-Platinum

The 10% rhodium-platinum alloy is stronger at all temperatures than pure platinum. This alloy should be used where the physical conditions are arduos. It isnot recommended for applications where repeated fusions are likely, since it is less resistant than LA platinum to these processes. Other rhodium-platinum ratios are available on request.

– Gold-Platinum

5% Gold_platinum is the material most commonly used at present. Where additionalstrenght is required, rhodium is added to form the ternary alloy 3% gold-10% rhodium-87% platinum.
However, finding increasing application in this area is a new Johnson Matthey material, ZGS 5% gold-platinum. This zirconia grain stabilised, non wetting material gives all the strenght of the rhodium-containing ternary alloy without the additional expense of rhodium or the extra fabrication problems that the ternary alloy provides. The resistance of this material to progressive contamination from impurities in the melt, which are frequently the cause of failure in this type of application, is outstanding.

– Silver

Silver apparatus is sometimes preferred for fusions with alkali hydroxides

– Gold

This material is sometimes used for hyroflouric acid treatment of silicious materials.

– Iridium

Iridium has a high melting point (2443°) and chemical inertness at elevated temperatures.
Pure iridium crucibles are widely used for the growing of crystals from high-purity melts at temperatures of up to 2200°C.

– Operating Temperatures

The following are the reccomended maximum operating temperatures for our laboratory apparatus materials:

– ZGS Platinum

In 1968 Johnson Mattey introduced its grain stabilised product, ZGS platinum, to the apparatus market. Thisproduct, which is pure platinum stabilised by the addition of a small amount of zirconia, exhibits remarkable and advantageous properties when used as a high-temperature material.

The zirconla is finely dispersed within the metal matrix and the grains have a high aspect ratio. The stabilised structure gives greatly improved hot strenght characteristics over conventional alloys. In addition, the extended grain boundary path of such a highly linear structure provides increased resistance to attack along its grain boundaries by deleterious elements such as base metals.