ANALYSIS OF ALTERNATIVES non-confidential report Legal name of applicant(s): ZF Luftfahrttechnik GmbH Submitted by: ZF Luftfahrttechnik GmbH Substance: Chromium trioxide EC No: 215-607-8, CAS No: 1333-82-0 Use title: Surface treatment for applications in the aeronautics and aerospace industries, unrelated to Functional chrome plating or Functional chrome plating with decorative character Use number: 4 ANALYSIS OF ALTERNATIVES Disclaimer This document shall not be construed as expressly or implicitly granting a license or any rights to use related to any content or information contained therein. In no event shall applicant be liable in this respect for any damage arising out or in connection with access, use of any content or information contained therein despite the lack of approval to do so. ii Use number: 4 ZF Luftfahrttechnik GmbH ANALYSIS OF ALTERNATIVES CONTENTS 1. SUMMARY ............................................................................................................................................................ 1 2. ANALYSIS OF SUBSTANCE FUNCTION.......................................................................................................... 6 2.1. The substance ................................................................................................................................................. 6 2.2. Uses of chromium trioxide ............................................................................................................................. 6 2.3. Purpose and benefits of chromium trioxide .................................................................................................... 6 3. ANALYSIS OF SUBSTANCE FUNCTION.......................................................................................................... 8 3.1. Usage .............................................................................................................................................................. 8 3.2. Surface treatment processes ............................................................................................................................ 13 3.2.1. Pre-treatment processes ................................................................................................................................. 15 3.2.1.1 Functional cleaning ..................................................................................................................................... 15 3.2.1.2 Pickling and etching .................................................................................................................................... 15 3.2.1.3 Deoxidising ................................................................................................................................................. 16 3.2.1.4 Stripping ...................................................................................................................................................... 17 3.2.2. Main surface treatment processes.................................................................................................................. 17 3.2.2.1 Chemical conversion coating (including phosphate conversion coating: phosphating) .............................. 17 3.2.2.2 Chromic acid anodising (CAA) ................................................................................................................... 18 3.2.2.3 Passivation of stainless steel ....................................................................................................................... 19 3.2.2.4 Sacrificial coatings ...................................................................................................................................... 19 3.2.2.5 Slurry (diffusion) coatings .......................................................................................................................... 20 3.2.3. Post-treatment processes ............................................................................................................................... 20 3.2.3.1 Sealing after anodizing ................................................................................................................................ 20 3.2.3.2 Passivation of metallic coatings .................................................................................................................. 21 3.2.3.3 Chromium trioxide rinsing (after phosphating) ........................................................................................... 21 3.3. Key chromium trioxide functionalities in surface treatment processes .......................................................... 21 3.3.1. Pre-treatments - key functionalities ............................................................................................................... 22 3.3.1.1 Functional cleaning, pickling, etching ........................................................................................................ 22 3.3.1.2 Deoxidising ................................................................................................................................................. 22 3.3.1.3 Stripping of inorganic finishes (e.g. conversion coatings, anodic coatings) ............................................... 22 3.3.1.4 Chemical stripping of organic coatings (e.g. primers, topcoats and specialty coatings) ............................. 23 3.3.2. Key functionalities of chromium trioxide-based main processes & post-treatments .................................... 23 3.3.3. Key functionalities in the aerospace sector ................................................................................................... 25 4. ANNUAL TONNAGE............................................................................................................................................ 29 4.1. Annual tonnage band of chromium trioxide ................................................................................................... 29 5. GENERAL OVERVIEW ON THE SPECIFIC APPROVAL PROCESS IN THE AEROSPACE SECTOR ........ 30 5.1. General overview ............................................................................................................................................ 30 5.2. Development and qualification ....................................................................................................................... 33 5.2.1. Requirements development ........................................................................................................................... 33 5.2.2. Technology development .............................................................................................................................. 34 5.2.3. Qualification .................................................................................................................................................. 36 5.2.4. Certification .................................................................................................................................................. 37 5.2.5. Implementation / industrialisation ................................................................................................................. 38 5.2.6. Examples ....................................................................................................................................................... 40 6. IDENTIFICATION OF POSSIBLE ALTERNATIVES ......................................................................................... 41 6.1. Description of efforts made to identify possible alternatives .......................................................................... 41 6.1.1. Research and development ............................................................................................................................ 41 6.1.2. Data searches ................................................................................................................................................. 42 6.2. Consultations .................................................................................................................................................. 42 6.3. List of possible alternatives ............................................................................................................................ 42 7. SUITABILITY AND AVAILABILITY OF POSSIBLE ALTERNATIVES ......................................................... 44 7.1. Main Processes & Post-treatments ................................................................................................................. 44 CATEGORY 1 ALTERNATIVES ............................................................................................................................... 44 7.1.1. ALTERNATIVE 1: Acidic surface treatments ............................................................................................. 44 7.1.1.1 Substance ID and properties ........................................................................................................................ 44 7.1.1.2 Technical feasibility .................................................................................................................................... 45 7.1.1.3 Economic feasibility .................................................................................................................................... 51 7.1.1.4 Reduction of overall risk due to transition to the alternative ...................................................................... 51 7.1.1.5 Availability (R&D status,