THE ENGINE REBUILDER ASKED A FEW MORE QUESTIONS ABOUT THE USE OF COBALT
WHY IS COBALT USE IN THE INDUSTRY SO EXTENSIVE? Wear-resistant materials that are effective at low to moderate temperatures, such as brass or plastic, lose their mechanical strength at hi�h tem�eratures� �aterials that are s�ecifically de�elo�ed for hi�h temperatures succeed by generating oxidation products between the contact surfaces which act as a lubricating layer, but this mechanism doesn’ t work until the temperature e�ceeds a �i�en threshold�
The trigger point for forming such a tribolayer is relatively low at ~ 200 ° C with Cobaltbase materials, providing high levels of abrasive and adhesive wear resistance combined with effective corrosion resistance, all the way up to temperatures of ������ or more� �t�s this extensive range which makes it so useful and why Cobalt has become the go-to solution for demanding dry sliding bush set�u�s�
WHY TRY TO DEVELOP AN ALTERNATIVE TO COBALT? �ith �� �er cent of the �obalt mined globally now used for batteries in electrified �ehicles and with the ado�tion of ��s �rowin� si�nificantly year-on-year, the demand is correspondingly growing, which is pushing up the price – Tenneco only sees the �rice of �obalt risin��
Other factors, such as the controversy around Cobalt mining conditions and limited availability, all contribute to there bein� a stron� case for findin� an alternati�e� �he challen�e is to reduce the Cobalt content while still delivering robust products for applications such as shaft bushings for turbochargers and ��� �al�es�
The properties of Cobalt mean that automotive manufacturers have seen it as the ��roblem sol�er� solution� �f an alternati�e is de�elo�ed, the benefits to the automotive industry will be si�nificant� �hese include reduced component costs, a more stable price and lon��term sustainability�
WHAT WAS THE PROCESS OF DEVELOPING A LOW- COBALT ALTERNATIVE? �he �fi�e materials� used in the initial tests included cobalt content of 0, �, ��, �� and �� �er cent� �he tests were carried out in-house at Tenneco’ s �o�entry facility in the ���
HOW DID YOU VALIDATE THE NEW MATERIAL? The collaborative trials conducted with a major global vehicle manufacturer comparing the wear resistance of ������� a�ainst series �roduction materials in a test rig, simulated the installation and loading of a turbochar�er waste�ate bushin�� �he wear test was carried out at six different temperature points( 20, 100, 200, 300, ��� and ������ usin� new s�ecimens in
each case, with constant load application and each test runnin� for �� hours�
The results showed that at 200 ° C ������� dis�lays a si�nificantly reduced wear compared to a Cobaltfree material and is comparable to the results of the high-Cobalt material, �������� �t all other tem�eratures the new material’ s performance closely mirrored �������� �n�esti�ations showed that ������� is formin� a tribolayer like the high-Cobalt material, e��lainin� the �ood �erformance�
HOW IS TENNECO CONTINUING ITS FURTHER DEVELOPMENT OF REDUCING COBALT CONTENT AND DEPENDENCE? The development work by Tenneco demonstrates that, currently, it is not yet possible to eliminate the use of Cobalt from the manufacture of demanding shaft�in�bushin� systems� �owe�er, testin� of ������� does �ro�e that it is possible to optimise the metallurgy and manufacturing processes to enable the provision of comparable performance characteristics with a reduction in �obalt�
Two further stages of development work are currently underway – test components produced using ������� are currently bein� e�aluated in a range of customer applications, and additional shaft materials are being assessed with a view to further e��loration� �enneco remains focused on the further development of materials in this �ey field�
BELOW: FM-T88A microstructure( 500 × magnified). ABOUT THE NEW TENNECO – THE FUTURE POWERTRAIN TECHNOLOGY COMPANY Following Tenneco’ s expected separation to form two independent companies, an Aftermarket and Ride Performance company( DRiV™) as well as a new Powertrain Technology company, the new Tenneco will be one of the world’ s largest pure-play powertrain companies serving OE markets worldwide, with engineered solutions addressing fuel economy, power output, and criteria pollution requirements for gasoline, diesel and electrified �owertrains� �he new Tenneco would have 2019 revenues of ������ billion, ser�in� li�ht �ehicle, commercial truck, off-highway and industrial mar�ets� www. tenneco. com
45