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Title: Use of coupled passivants and consolidants on calcite mineral surfaces

Abstract

Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than themore » commercial product Conservare{reg_sign} OH and at least as well as Conservare{reg_sign} H. The modeling results indicate that there may be a threshold binding energy for the passivant above which the dissolution rate of calcite is actually enhanced. More strongly-binding passivants may aid in the dissolution mechanism or dissociate in aqueous solution exposing the calcite surface to water.« less

Authors:
; ; ;  [1];  [2]
  1. Sandia National Labs., Albuquerque, NM (United States)
  2. Naval Research Lab., Washington, DC (United States). Optical Sciences Div.
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
441661
Report Number(s):
SAND-97-0239C; CONF-961202-40
ON: DE97002531; TRN: AHC29705%%6
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: 1996 Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 2-6 Dec 1996; Other Information: PBD: [1997]
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCITE; CORROSION PROTECTION; BUILDING MATERIALS; CULTURAL OBJECTS; CORROSION INHIBITORS; PROTECTIVE COATINGS; WEATHERING; MATERIALS TESTING; PASSIVATION; MOLECULAR MODELS

Citation Formats

Nagy, K.L., Cygan, R.T., Brinker, C.J., Ashley, C.S., and Scotto, C.S. Use of coupled passivants and consolidants on calcite mineral surfaces. United States: N. p., 1997. Web.
Nagy, K.L., Cygan, R.T., Brinker, C.J., Ashley, C.S., & Scotto, C.S. Use of coupled passivants and consolidants on calcite mineral surfaces. United States.
Nagy, K.L., Cygan, R.T., Brinker, C.J., Ashley, C.S., and Scotto, C.S. Sat . "Use of coupled passivants and consolidants on calcite mineral surfaces". United States. doi:. https://www.osti.gov/servlets/purl/441661.
@article{osti_441661,
title = {Use of coupled passivants and consolidants on calcite mineral surfaces},
author = {Nagy, K.L. and Cygan, R.T. and Brinker, C.J. and Ashley, C.S. and Scotto, C.S.},
abstractNote = {Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than the commercial product Conservare{reg_sign} OH and at least as well as Conservare{reg_sign} H. The modeling results indicate that there may be a threshold binding energy for the passivant above which the dissolution rate of calcite is actually enhanced. More strongly-binding passivants may aid in the dissolution mechanism or dissociate in aqueous solution exposing the calcite surface to water.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Feb 01 00:00:00 EST 1997},
month = {Sat Feb 01 00:00:00 EST 1997}
}

Conference:
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