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Third-Level Packaging Materials
Published in Mitel G. Pecht, Rakesh Agarwal, Patrick McCluskey, Terrance Dishongh, Sirus Javadpour, Rahul Mahajan, Electronic Packaging: Materials and Their Properties, 2017
Mitel G. Pecht, Rakesh Agarwal, Patrick McCluskey, Terrance Dishongh, Sirus Javadpour, Rahul Mahajan
Beryllium-copper is a common contact material due to its good spring properties and corrosion resistance. Beryllium-copper exhibits high strength, hardness, fatigue endurance and wear resistance. The yield strength is usually in the range of 550 to 1137 MPa. Due to the high strength of beryllium-copper, the spring contacts can be made small. Beryllium-copper (Be-Cu) can be formed in any direction without fracturing. Thus, complex shapes and sharper bends in pins and contacts can be easily formed. Be-Cu also has high resistance to anelastic (defined as time-dependent elastic strain) creep behavior and resistance to stress relaxation. Corrosion resistance, high electrical conductivity, the highest hardness among copper-base alloys and good wear resistance all contribute to make BeCu an ideal spring contact material for connectors.
Opto-Mechanical Characteristics of Materials
Published in Paul Yoder, Daniel Vukobratovich, Opto-Mechanical Systems Design, 2017
This high-strength beryllium copper is used primarily for springs, clips, washers, and in electrical and electronic equipment. Machinability is good. It can be welded and brazed (with some difficulty). Soldering requires the use of activated flux. The machining of parts must be completed before aging or heat treating.
Contact Materials
Published in Milenko Braunovic, Valery V. Konchits, Nikolai K. Myshkin, Electrical Contacts, 2017
Milenko Braunovic, Valery V. Konchits, Nikolai K. Myshkin
Copper and copper alloys are used to a very large extent in low-current engineering for current-carrying spring components. Beryllium copper (0.1–2.0% Be) is a specially suitable spring contact material for connector applications due to its good mechanical properties, electrical and thermal conductivities, and resistance to wear and corrosion. It can retain its spring characteristics up to 150°C. Phosphorous bronze (1.3–10% Sn, 0.1–0.3% P) is also widely used as a spring material for connector applications. However, it should not be used at high stress levels at temperatures exceeding 107°C, nor in salt-containing atmospheres. Low-lead brass (0.3–0.8% Pb) is primarily used as rod stock for pin contacts, notably in rack- and panel-type connectors.
Processes for environmentally friendly and/or cost-effective manufacturing
Published in Materials and Manufacturing Processes, 2021
Selection of materials is important in industrial applications, and as a global trend, environmental issues must be taken into account. Plastic products are mass manufactured cost-effectively by injection molding, which is an advantage over manufacturing of products one by one. Aluminum and beryllium copper alloys were among the popular mold insert materials. However, due to their wear resistance issues, the advantages of aluminum alloys are compromised. On the other hand, breathing BeCu dust generated by machining of it could cause serious health problems. Hence, the wear rates, hardness and molding performance of the mold inserts made from turning of Al, rapidly solidified Al and BeCu alloys were investigated by Zhong et al. The BeCu and Al alloys had the lowest and highest wear rates, respectively. The rapidly solidified Al alloy had the wear rate value close to that of the BeCu alloy, and performed in molding of plastic lenses comparably to the BeCu alloy. This finding offers the industry an option for material selection, as beryllium is a toxic element and the rapidly solidified Al alloy may become a suitable insert material.[220]
Effect of Expanded Graphite on the Tribological Behavior of Tin–Bronze Fiber Brushes Sliding against Brass
Published in Tribology Transactions, 2020
Bo Luo, Chengshan Liu, Xinli Liu, Lei Zhang
In most service situations, the contact stability of the brush is required to be high, which is even more important than reducing friction and wear (Braunovic, et al. (19)). As can be seen from Figs. 5 and 6, the friction coefficient and wear rate of the brush reach a very low level when the EG content increases to 23.7%, but the stability of the friction and wear performance in long-term service is also very important. Figure 7 shows the friction and wear properties of the brush with 23.7 vol% of EG in long-term testing. The friction coefficient (0.25 ± 0.03) is very stable after running for 40 km as shown in Fig. 5. Due to long-term stable contact, the brush and the disc show lower wear rates (0.2 × 10−5 mm3/Nm and 0.47 × 10−5 mm3/Nm, respectively) than those shown in Fig. 6. Argibay, et al. (11) found a similar phenomenon when a beryllium–copper fiber brush was sliding against a copper disc. In a test over 10,000 km, its friction coefficient and wear rate tended to be stable with an increase in sliding distance.
Effect of Operating Temperature on Tribological Behavior of As-Plated Ni-B Coating Deposited by Electroless Method
Published in Tribology Transactions, 2018
Arkadeb Mukhopadhyay, Tapan Kr. Barman, Prasanta Sahoo
Tribological tests of the coatings are carried out on a pin-on-disc type tribological test setup at room temperature and at 100, 300, and 500°C according to ASTM standard G99-05 (reapproved 2010). The Ni-B-coated pin specimens are held stationary against a rotating counterface material (Ø115 mm × 8 mm thick) of EN-31 specification hardened to 58–62 HRc. Test parameters such as the applied normal load, sliding speed, and sliding distance are kept fixed at 10 N, 0.419 m/s, and 502.8 m, respectively. The sliding duration and track diameter are 1,200 s and 80 mm, respectively. Tribological tests at elevated temperature are carried out by heating the counterface disc to the required temperature. A 15-kVA high-frequency induction heating machine with coils made of beryllium copper is used to heat the counterface disc. The temperature of the disc is continuously recorded by a pyrometer having a least count of 1°C and an accuracy of 1 ± 1% of measured temperature. Frictional force is measured using a button-type load cell with 10 kg capacity and an accuracy of 0.1 ± 1% of measured force. The wear rate is calculated from mass loss of the coatings as (Krishnaveni, et al. (32))where w is the mass loss (g), l is the sliding distance (m), and L is the applied normal load (N). The mass loss is obtained immediately after the sliding wear tests using a precision weighing balance with a readability of 0.01 mg to ensure accuracy of the results.