MIOX in Brake Pads. Case Study

Transcription

1 Case Study MIOX in Brake Pads GMBH SCHLOSS 1 A-9400 WOLFSBERG AUSTRIA TEL: +43 (4352) FAX: +43 (4352) miox@kmi.at Content Materials... 2 Test procedure and performed tests... 2 Physical results of the mixture... 4 Physical results of pads... 4 Visual examination of the pads... 6 Friction results... 6 Noise Index... 9 Conclusions Appendix Page 1/13 Issued:

2 MIOX for Friction Material Brake Pads KMI is market leader in Micaceous Iron Oxide products with the registered trade name MIOX. The objective of this case study is the evaluation of the influence of MIOX AS on brake pads in disk brake pads commonly used in Europe. The case study shows that MIOX substitutes alternative abrasives like Zirconium Silicate or Potassium Titanate with similar and even better technical performance at lower cost. Materials MIOX is micaceous Iron Oxide Fe 2 O 3. Its lamellar structure provides a high aspect ratio, as shown in Figure 1 which is an important distinction to the usual, similar but granular Hematite. Figure 1: MIOX - abrasive with lamellar particles MIOX is compared to Zirconium Silicate and Potassium Titanate which are commonly used in disk brake pads. Table 1: Tested materials: MIOX AS was compared to Zirconium Silicate and Potassium Titanat Test Material Content Formulations No. 1-3 Content Formulations No. 4-6 Particle Size d 50 MIOX AS 3 wt-% 6 wt-% 35 m Comment Micaceous Iron Oxide high aspect ratio Zirconium Silicate CM 3 wt-% 6 wt-% 100 m Alroko Hamburg Potassium Titanate PM 3 wt-% 6 wt-% 6 10 m Alroko Hamburg Test procedure and performed tests All tests were conducted by Produco experts for friction material ( The tests were carried out with standard formulations which are commonly used in Europe for disc brake pads. Different mixtures were produced in a vertical mixer (Papenmeier High Speed Mixer with 3 impellers and pot mixing head, type TGHK, 8 l). All raw materials, including test materials were mixed all together in batches of 2 kg for 4 minutes. The mixer was emptied after 4 more minutes. The homogeneous material is put to press curing under following conditions: Pressure: 25 MPa Temperature: 155 C Period: 30 s pressure, 15 s degassing, 30 s pressure, 15 s degassing, 210 s pressure Total time: 300 s MIOX in Brake Pads rev03 EN page 2/13 Issued:

3 Table 2: 6 different formulations were tested Standard Formulation with 3 wt-% additive with 6 wt-% additive No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 [wt-%] [wt-%] [wt-%] [wt-%] [wt-%] [wt-%] Metal Filler 48,5 48,5 48,5 48,5 48,5 48,5 Lubriant Organic Fiber 1,5 1,5 1,5 1,5 1,5 1,5 Abrasive Resin Tested additive MIOX AS 3 6 Zirconium Silicate 3 6 Potassium Titanate 3 6 The following table shows all performed tests and testing standards. Table 3: Performed Tests and Testing Standards Test Unit Testing standard or procedure Bulk density [cm³/100g] 100 g sample, 250 ml measuring cylinder, 4 min mixing Dust Adhesion [%] 10 g material on 1mm Sieve, passing without vibration Height increase of green compact green strength [%] [N] pad shearing strength [N] ISO 6312 specific shearing strength [N/cm²] ISO 6312 compressibility (RT, 400 C) [m] ISO 6310 thermal transmission [ C] ISO 6310 thermal expansion [m] ISO 6310 measurement after 24 h green compact is vertically strained with brass strip (10x2mm) to destruction coefficient of friction - Dynamometer, AK-Master SAE J2522 brake pad wear [g] after AK-Master SAE J2522 disc wear [g] after AK-Master SAE J2522 visual examination noise behaviour before and after AK-Master SAE J2522 Dynamometer, SAE J2521 MIOX in Brake Pads rev03 EN page 3/13 Issued:

4 Physical results of the mixture Different physically tests indicate the behaviour of the mixture during processing. The tested mineral types show no significant differences in the physical analyses. The characteristics of MIOX correspond largely to the properties of the countertypes Zirconium Silicate and Potassium Titanate. The results show, that the processability and the handling of the green compact with addition of MIOX are very good. One criterion for the mixing behavior is the bulk volume. The addition of MIOX did not show any substantial change of the bulk volume. The formulation of MIOX show the same, low dust adhesion and also the height increase of the green compact after 24 h were comparably. There was no negative influence on the green strength the high green strength provides safe handling of the green compacts. See detail results in Figure 12 to Figure 16. Physical results of pads The shear strength with MIOX pressed pads are at the level of the compared products detail data you can find in the appendix, Figure 17 and Figure 18. Table 4: Physical results of the pads Formulation Compressibility at room temperature [m] Compressibility at 400 C [m] Thermal Transmission [ C] Thermal Expansion [m] MIOX AS No ,5 3 % Zirconium Silicate Potassium Titanate No ,8 No ,0 MIOX AS No ,3 6 % Zirconium Silicate Potassium Titanate No ,3 No ,8 The compressibility tests showed that MIOX behaves similarly in cold- and hot compressibility as compared products Zirconium Silicate and Potassium Titanate. Figure 2: Compressibility at room temperature MIOX in Brake Pads rev03 EN page 4/13 Issued:

5 Figure 3: Compressibility at 400 C Significant differences were detected in the increased thermal conductivity and in the lower thermal expansion. Increased thermal transmission and the lower thermal expansion of the friction material improve the HOT-SPOT formation on the brake discs under high thermal impact. HOT-SPOTs lead to vibrations during braking and uncertainness of the driver and should be largely avoided or reduced. Figure 4: Thermal Transmission of Brake Pad Figure 5: Thermal Expansion of Brake Pad MIOX in Brake Pads rev03 EN page 5/13 Issued:

6 Visual examination of the pads Initial pads (type Ford Taurus) possessed a closed, smooth surface after manufacturing. After the pads were strained in the AK-master test, they still had a closed, uniform surface, as can be seen in Figure 6 in direct comparison to the formulation with Zirconium Silicate. MIOX AS Zirconium Silicate initial final initial final Rotor (Inboard) Rotor (Inboard) Inner Pad Inner Pad Outer Pad Outer Pad Figure 6: Visual disc- and pad assessment after the AK-Master, MIOX compared to Zirconium Silicate Friction results Tests of the friction coefficients were carried out according to the AK-Master SAE J2522 with the pad type Ford Taurus. Table 5: Friction coefficients according to AK-Master SAE J2522, pad type Ford Taurus Formulation (3) (4.3) (4.5) (5) (6) (7) (8) (9) (10) (12) (13) (14) (15) av. MIOX AS Nr. 4 0,5 0,44 0,4 0,4 0,3 0,4 0,5 0,3 0,44 0,29 0,48 0,33 0,43 0,43 6 % Zirconium Silicate Potassium Titanate Nr. 5 0,5 0,44 0,4 0,4 0,3 0,4 0,4 0,3 0,41 0,33 0,42 0,34 0,39 0,41 Nr. 6 0,5 0,42 0,39 0,4 0,3 0,4 0,4 0,3 0,41 0,32 0,44 0,3 0,42 0,41 MIOX in Brake Pads rev03 EN page 6/13 Issued:

7 The friction coefficient results showed, that in general MIOX provide higher friction coefficients than the compared products Zirconium Silicate and Potassium Titanate. Therefore braking pads with MIOX are on the same or even higher level as commonly used frictions. Figure 7 shows the results for a formulation with 6 % MIOX. Results for the formulation with 3 % MIOX can be found in the appendix (Figure 19 and Table 8). Figure 7: Coefficients of Friction with addition of 6 % of tested additives (MIOX AS, Zirconium Silicate, Potassium Titanate) In the AK-master test also the disc- and brake pad wear were determined. The brake pad wear was at a comparable level at all tested products, however, the addition of MIOX tended to result in a lower brake pad wear, as shown in the following table and figures. Table 6: Pad- and disc wear after AK-Master Formulation Pad wear [g] Disc wear [g] MIOX AS No. 1 10,2 12,3 3 % Zirconium Silicate No. 2 11,2 14,3 Potassium Titanate No. 3 9,8 12,5 MIOX AS No. 4 10,4 11,6 6 % Zirconium Silicate No. 5 11,3 14,4 Potassium Titanate No. 6 11,0 12,8 MIOX in Brake Pads rev03 EN page 7/13 Issued:

8 Figure 8: Pad wear after AK-Master The lowest disc wear was reached with MIOX AS. The brake pad wear was reduced about 10 20% with addition of MIOX in comparison to other tested material. Figure 9: Disc wear after AK-Master MIOX in Brake Pads rev03 EN page 8/13 Issued:

9 Noise Index The Noise Index was investigated with 3 test raw materials with a concentration of 6%. Therefore the pads were tested on a dynamometer for noise testing according to SAE J2521 without anti-squeal shims. For the test new pads and discs were used. The noise tests showed for MIOX AS a Noise Index of 3,1; for Zirconium Silicate 3,9 and for Potassium Titanate only 2,1 (see Figure 10). The performance of MIOX AS in brake pads lay in between the performance of Potassium Titanate and Zirconium Silicate and MIOX AS showed a significant better noise behavior than Potassium Titanate. Figure 10: Noise Index of 3 tested products with 6% concentration The noise development depending on temperature is shown in Figure 11 and is on its best with MIOX AS at the temperature range up to 100 C, at temperatures from 125 C to 225 C, MIOX AS is between the compared products. Figure 11: Noise behavior as a function of temperature MIOX in Brake Pads rev03 EN page 9/13 Issued:

10 Conclusions The results have shown that MIOX can be used as a replacement product for Zirconium Silicate and Potassium Titanate in brake pads. In comparison to other tested products MIOX offers following features: Lower raw material costs Increase of thermal transmission Reduced thermal expansion Reduces Hot Spots Reduction of disc wear Reduction of pad wear Higher friction coefficient Comparable or improved noise behaviour Comparable compressibility at a room temperature and at 400 C Comparable physical characteristics Comparable processing behaviour The case study shows that MIOX substitutes alternative abrasives like Zirconium Silicate or Potassium Titanate with similar and even better technical performance at lower cost. Application recommendation: 5-15 m% MIOX AS MIOX in Brake Pads rev03 EN page 10/13 Issued:

11 Appendix Figure 12: Bulk density of the mixture Figure 14: Height of green compact Figure 13: Dust adhesion of the mixture Figure 15: Height increase of green compact after 24 h MIOX in Brake Pads rev03 EN page 11/13 Issued:

12 Figure 16: Green strength Figure 18: Specific shearing strength Figure 17: Pad shearing strength Figure 19: Coefficient of Friction with addition of 3% (AK-Master) MIOX in Brake Pads rev03 EN page 12/13 Issued:

13 Table 7: Physical results Formulation Bulk density n.4' [cm3/100g] Dust adhesion [%] Height of green compact I [mm] Height of green compact II [mm] Height increase of green compact after 24 h [%] Green strength [N] Pad shearing strength [N] Specific shearing strength [kp/cm²] MIOX AS No ,1 10,8 10,9 0, % Zirconium Silicate Potassium Titanate No ,4 10,99 11,02 0, No ,3 11,08 11,15 0, MIOX AS No ,3 12,11 12,18 0, % Zirconium Silicate Potassium Titanate No ,3 10,82 10,91 0, No ,4 10,86 10,99 1, Table 8: Friction coefficients with 3% of tested additives Formulation (3) (4.3) (4.5) (5) (6) (7) (8) (9) (10) (12) (13) (14) (15) av. MIOX AS No. 1 0,5 0,43 0,39 0,4 0,3 0,4 0,4 0,3 0,42 0,32 0,43 0,34 0,42 0,42 3 % Zirconium Silicate Potassium Titanate No. 2 0,5 0,41 0,38 0,4 0,3 0,4 0,4 0,3 0,41 0,33 0,42 0,34 0,41 0,4 No. 3 0,5 0,48 0,42 0,5 0,4 0,5 0,5 0,3 0,43 0,33 0,45 0,33 0,43 0,45 MIOX in Brake Pads rev03 EN page 13/13 Issued: