1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
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3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AIR5567A AEROSPACEINFORMATION REPORTAIR5567 REV. A Issued 2009-05 Reaffirmed 2015
5、-08 Superseding AIR5567 Test Method for Catalytic Carbon Brake Disk Oxidation RATIONALE INTRODUCTION Runway deicing chemicals are currently approved with reference to specifications AMS1431 & AMS1435. Currently these specifications do not consider the issue of runway deicer compatibility with carbon
6、-carbon composite friction materials extensively used in aircraft brakes. Carbon is hygroscopic and porous, and therefore readily absorbs liquids and contaminants. Since these chemicals were first introduced in the early 1990s chemical analysis of worn brakes has shown increasing contamination with
7、alkali metal for operators with route structures which encounter icing conditions. Contamination with alkali metal catalysts increases the rate of oxidation for a given temperature exposure to a point where the degree of oxidation may be significant even for brakes subjected to typical service condi
8、tions. The impacts of oxidation can be severe from loss of refurbishment yield to loss of friction area and reduction in disc strength to a point where drive tenons or drive lugs break and the performance of the brake can be impacted. There have been growing demands from operators and airworthiness
9、authorities for a test to assess the impact of deicing chemicals on carbon oxidation. AIR5567A has been reaffirmed to comply with the SAE five-year review policy. TABLE OF CONTENTS 1. SCOPE 32. REFERENCES 32.1 SAE Publications . 32.2 Other Applicable Documents 33. OXIDATION TEST METHOD FOR ANTI-OXID
10、ANT (AO) TREATED COUPONS 33.1 Test Coupons 33.2 Generic AO mixing instructions . 43.3 Application of Anti-oxidant Protection System: Generic AO treatment . 43.4 Contamination of coupons Various 25% w/w runway deicer solutions . 53.5 Oxidation Testing 64. OXIDATION TEST RESULTS FOR AO TREATED COUPONS
11、 74.1 Test Laboratory reporting of Results 74.2 Reporting of Results as part of AMS1431 and AMS1435 75. NOTES 8 APPENDIX APPENDIX A TEST DATA TO SUBSTANTIATE METHOD . 9APPENDIX B DEVELOPMENT HISTORY OF TEST METHOD . 10 LIST OF FIGURES FIGURE A1 ROUND ROBIN TEST DATA 9FIGURE B1 HILL AIR FORCE BASE OX
12、IDATION TEST DATA ON BARE C4000CARBON AT 700 C . 11FIGURE B2 COVENTRY OXIDATION TESTS ON BARE C4000CARBON AT 600 C 12FIGURE B3 COVENTRY OXIDATION TESTS ON BARE C4000CARBON AT 550 C 12FIGURE B4 AKRON OXIDATION TESTS ON BARE C4000CARBON AT 550 C . 13FIGURE B5 ROUND ROBIN TEST DATA ON BARE C4000SAMPLES
13、 CONTAMINATED WITH VARIOUS 25W/W% DEICERS . 14FIGURE B6 EVOLUTION OF TEST PROCEDURE . 16 LIST OF TABLES TABLE B1 AVERAGE WEIGHT LOSS DATA FOR BARE C4000 CARBON SAMPLES TESTED AT TWO LOCATIONS. 14TABLE B2 AVERAGE WEIGHT LOSS DATA FOR C4000 CARBON SAMPLES COATED WITH GENERIC AO TESTED AT TWO LOCATIONS
14、. 15TABLE B3 MEAN NORMALIZED WEIGHT LOSS DEICER CONTAMINATED COUPONS FOR C4000 CARBON SAMPLES COATED WITH GENERIC AO TESTED AT TWO LOCATIONS. . 15 SAE INTERNATIONAL AIR5567A 2 OF 161. SCOPE The scope of the test method is to provide stakeholders including fluid manufacturers, airport operators, brak
15、e manufacturers, aircraft constructors, aircraft operators and airworthiness authorities with a relative assessment of the effect of deicing chemicals on carbon oxidation. This simple test is only designed to assess the relative effects of runway deicing chemicals by measuring mass change of contami
16、nated and bare carbon samples tested under the same conditions. It is not possible to set a general acceptance threshold oxidation limit based on this test method because carbon brake stack oxidation is a function of heat sink design and the operating environment. 2. REFERENCES The following publica
17、tions form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references ci
18、ted herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, TEL: 877-606-
19、7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS1431 Compound, Solid Runway and Taxiway Deicing/Anti-Icing AMS1435 Fluid, Generic, Deicing/Anti-Icing, Runways and Taxiways AIR5490 Carbon Brake Contamination 2.2 Other Applicable Documents Available from ASTM International,
20、 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA19428-2959, TEL: 610-832-9585, www.astm.org. ASTM C1179-91 Standard Test Method for Oxidation Mass Loss of Manufactured Carbon and Graphite Materials in Air 3. OXIDATION TEST METHOD FOR ANTI-OXIDANT (AO) TREATED COUPONS 3.1 Test Coupons a.
21、Material: Carbon/carbon composite brake material CARBENIX4000 (C4000), Honeywell Aircraft Landing Systems, 3520 Westmoor Street, South Bend, IN 46628, United States. (Note: C4000was agreed by all brake manufactures to be a suitable material which would give results representative of all carbon-carbo
22、n brake manufacturers materials. Alternate carbon materials/sources may be available in the future.) b. Configuration: Right cylinder cut from production aircraft brake discs. Dimensions, 49.911 0.127 mm, (1.965 0.005 inch) diameter, orientated parallel to the wear face of the as manufactured produc
23、tion brake discs and, 5.969 0.127 mm (0.235 0.005 inch) long, orientated through the thickness of the disc. Note no lubricants to be used during machining. Honeywell drawing number AX-36536. Coupon weight as supplied to be 19.800+/- 0.500 g. (Weight limits based on Honeywell C4000. Note alternative
24、carbon sources will require different weight specification limits. c. Identification Coupons will be supplied with unique engraved identification numbers. d. At all times coupons will be handled using single use vinyl or lint-free nylon gloves. e. Coupons will be ultrasonic cleaned, by the test hous
25、e, with one of the following fluids acetone, isopropyl alcohol, or de-mineralised water at room temperature for 10 minutes. SAE INTERNATIONAL AIR5567A 3 OF 16f. Coupons will be dried after cleaning at 110 qC for 2 to 4 hours prior to preliminary weigh. Dried coupons will be stored in a desiccator. g
26、. Weigh and record initial weights of all coupons to 0.001g accuracy or better. Return coupons to desiccator after weighing. (Initial weight (a) h. Rank coupons in weight (density) order. Allocate each ranked coupon in order to alternate groups according to how many groups required such that each se
27、eded coupon group reflects the mean and range of the total population. Minimum group size will be 8 coupons. 3.2 Generic AO mixing instructions a. Consult relevant Materials Safety Data Sheet (MSDS) and wear appropriate personal protective equipment. b. Formulation of generic Anti-Oxidant (AO) solut
28、ion is as follows: x 50wt % Mono Aluminium Phosphate (MALP) Composition Recommended supplier Sigma-Aldrich Product number 06234, brand name (FLUKA). o Aluminium Dihydrogen Phosphate (CAS 13530-50-2) (= 48% = 48% =85wt %) o Water (CAS 7732-18-5) ( 25w/w % concentration, dilute with the appropriate we
29、ight of demineralised water to achieve a 25w/w% solution according to the following formula. Where Wt DEMIN = Weight in grams of demineralised water required to achieve dilution to 25% w/w. Wt CONC = Weight in grams of concentrated deicer solution. w/w% CONC = weight for weight % concentration of de
30、icer concentrate. 3. Dilute required weight of concentrated deicer solution with appropriate weight demineralised water according to the above formula to give 25%w/w solution. b. Refer to relevant MSDS before using runway deicer solution. Wear specified personal protective equipment. Pour a minimum
31、of 0.5 litres of 25% w/w deicer solution per 8 samples to be immersed into a large flat bottomed glass vessel. c. Prepare a minimum of 8 AO coated coupons per solution plus 8 additional AO coated coupons for baseline tests. d. Careful segregation will be maintained between deicer treated and control
32、 coupons to avoid cross contamination. Coupons will be placed on individual dried dedicated high density, high purity alumina discs. e. Fully immerse 8 coupons in runway deicer (25% w/w concentration) in a large glass flat bottomed vessel such that coupons lie flat on the bottom of the vessel in a s
33、ingle layer. Fully immerse coupons for 10 minutes + 1 minute/ - 0 minutes turn them over after 5 minutes +/- 1 minute to expose all surfaces to solution. After 10 minutes + 1 minute/ -0 minutes remove coupons and shake off excess fluid. Wt DEMIN = (Wt CONC * w/w% CONC/100) * 3 Wt CONC * (1-w/w% CONC
34、/100) SAE INTERNATIONAL AIR5567A 5 OF 16f. Dry deicer contaminated coupons in glass vessel for 2 hours at 150 qC ensuring no cross contamination by careful segregation with baseline coupons. Remove the coupon sample group and immediately transfer to a separate dedicated desiccator and cool for a min
35、imum of 30 minutes to achieve room temperature. g. Weigh and record initial weights of all coupons to 0.001g accuracy or better immediately prior to test. (Initial weight (c) NOTE - Do not allow coupons to stand in air prior to weighing. Some deicing chemicals (e.g. Potassium acetate) react with moi
36、sture in the air. After weighing return coupons to desiccator. h. Calculate the percentage pick up of deicer for each coupon immersed in deicer. uppick %wt.100(a) wt initial(b) wt initial(c). wt initial i. Repeat steps a to h for each deicing chemical to be tested. j. Record mean percentage pick up
37、of deicer for each group of coupons. 3.5 Oxidation Testing a. Place each individual coupon centrally on its base in a clean refractory dish/ base on a large high temperature tray capable of withstanding prolonged exposure to 1022 F (550 C) such that a minimum spacing of 1 inch all round is achieved.
38、 Alternate coupons on the tray such that both contaminated and uncontaminated (baseline) coupons are tested simultaneously. b. Select a calibrated still air muffle furnace which can achieve 1022 qF 10 F or better (550 +/- 5 qC). Survey furnace temperature prior to test to establish suitability of eq
39、uipment. All areas of the furnace must achieve the required temperature stability performance. c. Load sample tray into preheated furnace and position control thermocouple centrally between the coupons. d. Maintain furnace temperature at 1022 qF 10 F or better (550 +/- 5 qC) in still air. Record tem
40、perature readings from the work load thermocouple either using a chart recorder or by periodic measurements. e. After 24 hours immediately remove the hot coupons with tray from the furnace and allow coupons to air cool for a minimum of 1 hour. Once coupons cooled sufficiently to allow handling trans
41、fer the coupons in a desiccator to achieve room temperature. Weigh each coupon and record coupon weight to 0.001g accuracy or better. (Final weight (d) f. Continue testing until all coupons are tested and weighed. g. Calculate the percentage oxidation weight loss for each coupon as follows: loss %wt
42、.100(a) wt initial(d) wt final(b). wt initial NOTE - some of the weight loss included in final weight “d” results from thermal decomposition of the deicer. It would be possible to quantify this effect, but at the expense of complicating the method by the inclusion of an additional thermal stabilizat
43、ion and weighing step. The calculated weight loss, for the contaminated coupons, calculated in step “vii” is a minimum value for weight loss through carbon oxidation based on an assumption the deicer sees 100% thermal decomposition weight loss. This is considered acceptable provided that test condit
44、ions are designed such that thermal decomposition weight is small relative to the carbon oxidation weight loss in the presence of strong oxidation catalysts. SAE INTERNATIONAL AIR5567A 6 OF 16h. Calculate the mean percentage oxidation weight loss and corresponding standard deviation for each group o
45、f coupons i. For each sample calculate the ratio of deicer pick up (section 3.4 (h) divided by AO pick up (section 3.3 (i). Calculate the mean of this ratio for each group of coupons. j. For each sample calculate normalized oxidation weight loss by dividing the oxidation weight loss (section 3.5 (g)
46、 by the ratio calculated in section 3.5 (i). k. Calculate the mean normalized oxidation weight loss and standard deviation for each group of coupons. l. Report results for each deicer solution as follows: 4. OXIDATION TEST RESULTS FOR AO TREATED COUPONS 4.1 Test Laboratory reporting of Results It is
47、 recommended that the following information is recorded and reported for each test to capture relevant test control data and assess scatter of results. Date Test Location 4.2 Reporting of Results as part of AMS1431 and AMS1435 When performing AIR5567 as part of AMS1431 and AMS1435 a simplified repor
48、t format can be adopted. The mean normalized weight loss deicer contaminated coupons (Section 3.5 k) may be utilized as “mean normalized carbon weight loss (%)” and reported as the measure of performance. Date Test Location Use one table for each deicer tested The lower the % weight loss the lower the risk of the carbon-carbon heat sink being damaged through catalytic oxidation. Deicer name Deicer supplier Deicer concentration Mean pick up of deicer in coupon (%) Section 3.4 (j) Mean pick up of AO in coupons (%) Section 3.3 (k) Mean ratio deicer pick up (%)/ AO pick up (%) Section 3.5 (i
