Aluminum oxide is a product artificially obtained by melting in electric furnaces and slow cooling Bauxite and subsequently ground and classified into various types and particle size. It is a high hardness material (9 on Mohs scale), with a specific weight of 3.2g / cm3 and the grains have sharp and sharp edges.
For blasting, the most used type is the so-called HSG found in the market classified between 16 and 220 mesh. For very special applications other types may be employed which are more purified or classified in finer particle size, usually in wet jet equipment.
The physical, chemical and geometrical characteristics of the grains, associated with the commercial availability of regular classifications, open for aluminum oxide, a wide and peculiar field of application in blasting.
The process is highly abrasive which is an important quality for some applications: – Removal of very hard scale;
– Preparation of surfaces for malting, electroplating and painting and controlled roughness for anchoring, especially in parts of high surface hardness.
– For the same reasons, it is also used for surface preparation for adherence of high liability coatings;
– In addition to good cleaning quality, some surface imperfections can be reduced or even eliminated.
In certain cases, the chemical composition of aluminum oxide and the absence of certain types of contamination form the blasting process compatible with some applications:
– Cleaning of titanium for plasma adhesion, widely used in aeronautical industry and maintenance;
– Cleaning of noble alloys such as cobalt chromium in dental prosthesis;
– General cleaning of non-ferrous metals, whether or not precious, when contamination with silica (sand) or iron (sand and steel grit) is not permitted.
In addition to cleaning, other deburring and satin finish applications can be obtained with aluminum oxide blasting and will be dealt with in later information.