A chamberless, remote plasma deposition process has been used to coat silicon and plastic substrates with glass at ambient conditions. The films were deposited by introducing an organosilane precursor into the afterglow of an atmospheric plasma fed with helium and 2 vol% oxygen. The precursors examined were hexamethyldisilazane, hexamethyldisiloxane, tetramethyldisiloxane, tetramethylcyclotetrasiloxane and tetraethoxysilane. With hexamethyldisilazane, glass films were deposited at rates of up to 0.25 µm min −1 and contained as little as 13.0 mol% hydroxyl groups. These films exhibited low porosity and superior hardness and abrasion resistance. With tetramethyldisiloxane, glass films were deposited at rates up to 0.91 µm min −1. However, these coatings contained significant amounts of carbon and hydroxyl impurities (∼20 mol% OH), yielding a higher density of voids and poor abrasion resistance. In summary, the properties of glass films produced by remote atmospheric plasma deposition strongly depend on the organosilane precursor selected.
A law governing the change in the ductility of metals and alloys under pressure is given:where P is the hydrostatic pressure, elo¢,1 is the strain accumulated from the start of necking to fracture, f, necking stress and (df/ds) the coefficient of linear work hardening. This relation is derived from a newly proposed criterion of ductile fracture, viz. "constancy of hydrostatic tensile stress", which indicates that the change of ductility with pressure obeys a three halves power law. The observed increase in ductility of widely differing metals and alloys under pressure up to 10,000 kg/cm z has confirmed that the proposed criterion is acceptable.It is further shown that the ductilities of some copper alloys with low stacking fault energy, such as Cu Zn and Cu-Ge alloys, increases with pressure at the beginning but the increase stops at fairly low pressure, i.e. 3,500 ~ 4,000 kg/cm 2, and their ductilities become almost insensitive to the pressure applied. It is suggested that ductile fracture of metals with low stacking fault energy is dominated by a process which occurs not by the hydrostatic stress component but by shear stress only.
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