Effect of relative humidity on repetitive impact behavior of machined silicon nitride

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb05349.x· OSTI ID:7046444

Srinivasan, S R; Blau, P J ^[1]

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1. Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

Silicon nitride is a promising candidate material to replace metallic valves in internal combustion engines. Its attractive mechanical properties relative to conventional alloys are expected to lead to reduced valve wear. As valves operate under combined conditions of impact and sliding contact, the durability of Si[sub 3]N[sub 4] under a repetitive 45[degree] impact was studied to assess the performance of these materials as valves. A significant effect of relative humidity on the impact behavior of Si[sub 3]N[sub 4] was noticed. Humid conditions resulted in a significant increase in impact wear resistance. This increase appears to be related to the differences in fracture modes under humid versus dry conditions. A possible mechanism for the observed humidity effects in Si[sub 3]N[sub 4] is advanced to explain the change in fracture modes. Increased impact resistance is expected to be a useful property for valve materials, as engine atmospheres contain significant amounts of water vapor resulting from the combustion reactions.

• OSTI ID: 7046444
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:3; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
FLUIDS
GASES
IMPACT STRENGTH
MECHANICAL PROPERTIES
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
RELIABILITY
SILICON COMPOUNDS
SILICON NITRIDES
VAPORS
WATER VAPOR
WEAR RESISTANCE