Difference between revisions of "Passivation bending issue"
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When a surface is passivated with sixth row elements over a whole lengthe in the bonding plane direction it begins quite strongly to bend (like a bimetal stripe). | When a surface is passivated with sixth row elements over a whole lengthe in the bonding plane direction it begins quite strongly to bend (like a bimetal stripe). | ||
| − | + | Passivation bending can be troublesome when designing linear channels for sliding rails. | |
| + | To compensate the effect one can passivate the coplanar surface on the opposing side of a sheet of e.g. diamond exactly the same way. | ||
| + | Alternatively to mend the effect one can alternate the surface passivation method (e.g oxygen/sulfur) in an regular or irregular pattern. | ||
| + | |||
| + | '''To investigate:''' Could the elastic energy stored in strained structures reach dangerous levels? | ||
Revision as of 16:15, 29 December 2013
All DMEs need to have a passivated surface. This means they must not have any open bonds. To archive this one usually resorts to the nonmetals of the fifth to seventh main group of the periodic table counting hydrogen to the seventh.
With the elements of the seventh group passivation is in most cases as easy as plugging every open bond wit a single hydrogen or halogenide atom. What makes this method undisirable in many cases is that those single bonds aren't very stiff to shearing forces. When two such surfaces slide along each other there is unnecessarily high dissipation meaning friction.
For sliding surfaces it is optimal when sixth row elements (Oxygen Sulphur) are used in such a way that the sliding direction lies in the plane spanned from the two bonds. Fifth row elements (Nitrogen Phosphorus) will work reasonably well.
The problem (or good thing) now is that atoms aren't perfect building bricks. If they "have" different numbrers of bonds they have different sizes. When a surface is passivated with sixth row elements over a whole lengthe in the bonding plane direction it begins quite strongly to bend (like a bimetal stripe).
Passivation bending can be troublesome when designing linear channels for sliding rails. To compensate the effect one can passivate the coplanar surface on the opposing side of a sheet of e.g. diamond exactly the same way. Alternatively to mend the effect one can alternate the surface passivation method (e.g oxygen/sulfur) in an regular or irregular pattern.
To investigate: Could the elastic energy stored in strained structures reach dangerous levels?
